title = {The {{Dalton}} Quantum Chemistry Program System},
author = {Aidas, Kestutis and Angeli, Celestino and Bak, Keld L. and Bakken, Vebj{\o}rn and Bast, Radovan and Boman, Linus and Christiansen, Ove and Cimiraglia, Renzo and Coriani, Sonia and Dahle, P{\aa}l and Dalskov, Erik K. and Ekstr{\"o}m, Ulf and Enevoldsen, Thomas and Eriksen, Janus J. and Ettenhuber, Patrick and Fern{\'a}ndez, Berta and Ferrighi, Lara and Fliegl, Heike and Frediani, Luca and Hald, Kasper and Halkier, Asger and H{\"a}ttig, Christof and Heiberg, Hanne and Helgaker, Trygve and Hennum, Alf Christian and Hettema, Hinne and Hjerten{\ae}s, Eirik and H{\o}st, Stinne and H{\o}yvik, Ida-Marie and Iozzi, Maria Francesca and Jans{\'i}k, Branislav and Jensen, Hans J{\o}rgen Aa. and Jonsson, Dan and J{\o}rgensen, Poul and Kauczor, Joanna and Kirpekar, Sheela and Kj{\ae}rgaard, Thomas and Klopper, Wim and Knecht, Stefan and Kobayashi, Rika and Koch, Henrik and Kongsted, Jacob and Krapp, Andreas and Kristensen, Kasper and Ligabue, Andrea and Lutn{\ae}s, Ola B. and Melo, Juan I. and Mikkelsen, Kurt V. and Myhre, Rolf H. and Neiss, Christian and Nielsen, Christian B. and Norman, Patrick and Olsen, Jeppe and Olsen, J{\'o}gvan Magnus H. and Osted, Anders and Packer, Martin J. and Pawlowski, Filip and Pedersen, Thomas B. and Provasi, Patricio F. and Reine, Simen and Rinkevicius, Zilvinas and Ruden, Torgeir A. and Ruud, Kenneth and Rybkin, Vladimir V. and Sa{\l}ek, Pawel and Samson, Claire C. M. and {de Mer{\'a}s}, Alfredo S{\'a}nchez and Saue, Trond and Sauer, Stephan P. A. and Schimmelpfennig, Bernd and Sneskov, Kristian and Steindal, Arnfinn H. and {Sylvester-Hvid}, Kristian O. and Taylor, Peter R. and Teale, Andrew M. and Tellgren, Erik I. and Tew, David P. and Thorvaldsen, Andreas J. and Th{\o}gersen, Lea and Vahtras, Olav and Watson, Mark A. and Wilson, David J. D. and Ziolkowski, Marcin and {\AA}gren, Hans},
year = {2014},
journal = {WIREs Comput. Mol. Sci.},
volume = {4},
number = {3},
pages = {269--284},
issn = {1759-0884},
doi = {10.1002/wcms.1172},
abstract = {Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree\textendash Fock, Kohn\textendash Sham, multiconfigurational self-consistent-field, M\o ller\textendash Plesset, configuration-interaction, and coupled-cluster levels of theory. Apart from the total energy, a wide variety of molecular properties may be calculated using these electronic-structure models. Molecular gradients and Hessians are available for geometry optimizations, molecular dynamics, and vibrational studies, whereas magnetic resonance and optical activity can be studied in a gauge-origin-invariant manner. Frequency-dependent molecular properties can be calculated using linear, quadratic, and cubic response theory. A large number of singlet and triplet perturbation operators are available for the study of one-, two-, and three-photon processes. Environmental effects may be included using various dielectric-medium and quantum-mechanics/molecular-mechanics models. Large molecules may be studied using linear-scaling and massively parallel algorithms. Dalton is distributed at no cost from http://www.daltonprogram.org for a number of UNIX platforms. This article is categorized under: Software {$>$} Quantum Chemistry},
date-modified = {2022-03-23 11:39:31 +0100},
file = {/Users/monino/Zotero/storage/P5NGV3YN/Aidas et al. - 2014 - The Dalton quantum chemistry program system.pdf;/Users/monino/Zotero/storage/KEYKRMF8/wcms.html}
title = {Multiconfigurational Second-Order Perturbation Theory: A Test of Geometries and Binding Energies},
author = {Andersson, Kerstin and Roos, Bj{\"o}rn O.},
year = {1993},
journal = {Int. J. Quantum Chem.},
volume = {45},
number = {6},
pages = {591--607},
doi = {10.1002/qua.560450610},
abstract = {Abstract Multiconfigurational second-order perturbation theory is tested for the calculation of molecular structure and binding energies. The scheme is based on the Complete Active Space (CAS) SCF method, which gives a proper description of the major features in the electronic structure, independent of its complexity, accounts for all near degeneracy effects, and includes full orbital relaxation. Remaining dynamic electron correlation effects are in a subsequent step added using second-order perturbation theory with the CASSCF wave function as the reference state (CASPT2). The approach is applied to the calculation of equilibrium geometry and atomization energies for 27 benchmark molecules containing first-row atoms (the ``G1'' test). Large atomic natural orbital (ANO)-type basis sets are applied (5s4p3d2f for LiF and 3s2p1d for H). It is shown that the CASSCF/CASPT2 approach is able to predict the equilibrium geometry with an accuracy better than 0.01 \AA{} for bond distances and 0\,\textdegree\textendash 2\,\textdegree{} for bond angles. Calculated atomization energies are underestimated with between 3 and 6 kcal/mol times the number of extra electron pairs formed. The error in the heat of reaction for a number of isogyric reaction (no difference in number of pairs) varies between -2.5 and +1.0 kcal/mol. The same type of accuracy is obtained in calculations for excited states. The molecules B2, C2, FO, FOO, and FOOF have also been studied. Results for the first three molecules are in accordance with those of the benchmark molecules. The FO bond distance in FOO is predicted to be 0.02 \AA{} longer than experiment. The heat of formation for FOO is computed to be 2.9 kcal/mol with an uncertainty of {$\pm$}3 kcal/mol. Preliminary results for FOOF (obtained with a smaller basis set) indicate that the approach yields a somewhat too long FO bond distance (1.64 \AA{} compared to 1.58 \AA{} experimentally). 1993 John Wiley \& Sons, Inc.},
title = {The Cr{$_2$} Potential Energy Curve Studied with Multiconfigurational Second-Order Perturbation Theory},
author = {Andersson, K. and Roos, B.O. and Malmqvist, Per Aake. and Widmark, P.-O.},
year = {1994},
journal = {Chem. Phys. Lett.},
volume = {230},
number = {4},
pages = {391--397},
issn = {0009-2614},
doi = {10.1016/0009-2614(94)01183-4},
abstract = {The potential energy curve of the Cr2 ground state has been obtained by multiconfigurational second-order perturbation theory. In this study 6\textendash 8 singularities appear in the potential curve for bond distances ranging from 1.5 to 2.2 \AA. However, these singularities are weak enough to allow the determination of approximate spectroscopic constants. By employing a large atomic natural orbital (ANO) basis set of the size 8s7p6d4f and by including 3s, 3p correlation effects and relativistic corrections, the following values were obtained (experimental data within parentheses): equilibrium bond length re = 1.71 \AA{} (1.68 \AA ), harmonic vibrational frequency {$\omega$}e = 625 cm-1 (481 cm-1) and dissociation energy D0 = 1.54 eV (1.44{$\pm$}0.06 eV).},
title = {Different Forms of the Zeroth-Order Hamiltonian in Second-Order Perturbation Theory with a Complete Active Space Self-Consistent Field Reference Function},
author = {Andersson, K.},
year = {1995},
journal = {Theor. Chim. Acta},
volume = {91},
pages = {31--46},
doi = {10.1007/BF01113860},
abstract = {A new one-particle zeroth-order Hamiltonian is proposed for perturbation theory with a complete active space self-consistent field (CASSCF) reference function. With the new partitioning of the Hamiltonian, reference functions dominated by a closed-shell configuration, on one hand, and an open-shell configuration, on the other hand, are treated in similar and balanced ways. This leads to a better description of excitation energies and dissociation energies. The new zeroth-order Hamiltonian has been tested on CH2, SiH2, NH2, CH3, N2, NO, and O2, for which full configuration interaction (FCI) results are available. Further, excitation energies and dissociation energies for the N2 molecule have been compared to corresponding multireference (MR) CI results. Finally, the dissociation energies for a large number of benchmark molecules containing first-row atoms (the ``G1'' test) have been compared to experimental data. The computed excitation energies compare very well with the corresponding FCI and MRCI values. In most cases the errors are well below 1 kcal/mol. The dissociation energies, on the other hand, are in general improved in the new treatment but have a tendency to be overestimated when compared to other more accurate methods.},
title = {N-Electron Valence State Perturbation Theory: {{A}} Fast Implementation of the Strongly Contracted Variant},
shorttitle = {N-Electron Valence State Perturbation Theory},
author = {Angeli, Celestino and Cimiraglia, Renzo and Malrieu, Jean-Paul},
year = {2001},
month = dec,
journal = {Chem. Phys. Lett.},
volume = {350},
number = {3},
pages = {297--305},
issn = {0009-2614},
doi = {10.1016/S0009-2614(01)01303-3},
abstract = {In this work we reconsider the strongly contracted variant of the n-electron valence state perturbation theory (SC NEV-PT) which uses Dyall's Hamiltonian to define the zero-order energies (SC NEV-PT(D)). We develop a formalism in which the key quantities used for the second-order perturbation correction to the energy are written in terms of the matrix elements of suitable operators evaluated on the zero-order wavefunction, without the explicit knowledge of the perturbation functions. The new formalism strongly improves the computation performances. As test cases we present two preliminary studies: (a) on N2 where the convergence of the spectroscopic properties as a function of the basis set and CAS-CI space is discussed and (b) on Cr2 where it is shown that the SC NEV-PT(D) method is able to provide the correct profile for the potential energy curve.},
date-modified = {2022-03-23 11:39:37 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/TLCFMAR5/Angeli et al. - 2001 - N-electron valence state perturbation theory a fa.pdf;/Users/monino/Zotero/storage/FNM6L8SE/S0009261401013033.html}
title = {N-Electron Valence State Perturbation Theory: {{A}} Spinless Formulation and an Efficient Implementation of the Strongly Contracted and of the Partially Contracted Variants},
shorttitle = {N-Electron Valence State Perturbation Theory},
author = {Angeli, Celestino and Cimiraglia, Renzo and Malrieu, Jean-Paul},
year = {2002},
month = nov,
journal = {J. Chem. Phys.},
volume = {117},
number = {20},
pages = {9138--9153},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.1515317},
date-modified = {2022-03-23 11:39:47 +0100},
file = {/Users/monino/Zotero/storage/EJAG6JHM/Angeli et al. - 2002 - n-electron valence state perturbation theory A sp.pdf;/Users/monino/Zotero/storage/U54ZW8SQ/1.html}
title = {The Use of Local Orbitals in Multireference Calculations},
author = {Angeli, Celestino and Calzado, Carmen J. and Cimiraglia, Renzo and Evangelisti, Stefano and Guih{\'e}ry, Nathalie and Leininger, Thierry and Malrieu, Jean-Paul and Maynau, Daniel and Ruiz, Jos{\'e} Vicente Pitarch and Sparta, Manuel},
title = {A Multireference Coupled-Cluster Study of the Ground State and Lowest Excited States of Cyclobutadiene},
author = {Balkov{\'a}, A. and Bartlett, Rodney J.},
year = {1994},
month = aug,
journal = {J. Chem. Phys.},
volume = {101},
number = {10},
pages = {8972},
publisher = {{American Institute of PhysicsAIP}},
issn = {0021-9606},
doi = {10.1063/1.468025},
abstract = {The electronic structure of the ground state and several low-lying excited states of cyclobutadiene are studied using the new state-universal multireference coupled-cluster method with single and double excitations (MR-CCSD) augmented by a noniterative inclusion of the triple excitations [MR-CCSD(T)]. Two possible ground state configurations are examined, namely the square and the distorted rectangular geometries, and the multireference coupled-cluster energy barrier for the interconversion between the two rectangular ground state structures is estimated to be 6.6 kcal mol-1 compared with the best theoretical value, 6.4 kcal mol-1 obtained using the highly accurate coupled-cluster method with full inclusion of the triple excitations (CCSDT). The ordering of electronic states for the square geometry is determined, with the ground state singlet being located 6.9 kcal mol-1 below the lowest triplet electronic state. We also examine the potential energy surface for the interconversion between the two equivalent second-order Jahn\textendash Teller rhombic structures for the first excited singlet state. When comparing the MRCC energies with the results provided by various single- and multireference correlation methods, the critical importance of including both the dynamic and nondynamic correlation for a qualitatively correct description of the electronic structure of cyclobutadiene is emphasized. We also address the invariance properties of the present MRCC methods with respect to the alternative selections of reference orbital spaces.},
copyright = {\textcopyright{} 1994 American Institute of Physics.},
title = {A State-Specific Multi-Reference Coupled-Cluster Approach with a Cost-Effective Treatment of Connected Triples: {{Implementation}} to Geometry Optimisation},
shorttitle = {A State-Specific Multi-Reference Coupled-Cluster Approach with a Cost-Effective Treatment of Connected Triples},
author = {Banerjee, Debi and Mondal, Monosij and Chattopadhyay, Sudip and Mahapatra, Uttam Sinha},
year = {2016},
month = may,
journal = {Mol. Phys.},
volume = {114},
number = {10},
pages = {1591--1608},
publisher = {{Taylor \& Francis}},
issn = {0026-8976},
doi = {10.1080/00268976.2016.1142126},
abstract = {Recently, we have suggested an approximate state-specific multi-reference coupled-cluster (SS-MRCC) singles, doubles and triples method based on the CCSDT-1a+d approximation applied to the single-reference CC approach, in which the contribution of the connected triple excitations is iteratively treated. The method, abbreviated as SS-MRCCSDT-1a+d is intruder-free and fully size-extensive. It has been employed for geometry optimisations of various systems possessing quasi-degeneracy of varying degrees (like N2H2 and O3) by invoking numerical gradient scheme. The method is also applied to CH2 and square cyclobutadiene in their excited states. For all systems under study, the computed values are in good accordance with state-of-the-art theoretical estimates indicating that the method might be a promising candidate for an accurate treatment of geometrical parameters of states plagued by electronic degeneracy in a computationally tractable manner.},
title = {Density-Functional Exchange-Energy Approximation with Correct Asymptotic Behavior},
author = {Becke, A. D.},
year = {1988},
month = sep,
journal = {Phys. Rev. A},
volume = {38},
number = {6},
pages = {3098--3100},
publisher = {{American Physical Society}},
doi = {10.1103/PhysRevA.38.3098},
abstract = {Current gradient-corrected density-functional approximations for the exchange energies of atomic and molecular systems fail to reproduce the correct 1/r asymptotic behavior of the exchange-energy density. Here we report a gradient-corrected exchange-energy functional with the proper asymptotic limit. Our functional, containing only one parameter, fits the exact Hartree-Fock exchange energies of a wide variety of atomic systems with remarkable accuracy, surpassing the performance of previous functionals containing two parameters or more., This article appears in the following collection:},
title = {Analytical Representations of High Level Ab Initio Potential Energy Curves of the {{C}}{$_2$} Molecule},
author = {{Boggio-Pasqua}, M. and Voronin, A.I. and Halvick, Ph. and Rayez, J.-C.},
year = {2000},
month = oct,
journal = {J. Mol. Struct. THEOCHEM},
volume = {531},
number = {1-3},
pages = {159--167},
issn = {01661280},
doi = {10.1016/S0166-1280(00)00442-5},
abstract = {Realistic analytical representations of the twelve lowest singlet and triplet electronic adiabatic potential energy curves of C2 molecule are given in this article. The corresponding electronic states are correlated with C atoms both in their 3P state. A new set of high level MRCI calculations coupled with a double many-body expansion analytical \textregistered tting based on the extended Hartree{$\pm$}Fock approximate correlation energy model have been used in this work. Using RKR data available in the literature, comparison is made between our results and RKR turning points concerning the four lowest singlet states X1Sg1, A1Pu, B1Dg and BH 1Sg1 of C2. The agreement is very satisfying. q 2000 Elsevier Science B.V. All rights reserved.},
title = {Breaking the Carbon Dimer: {{The}} Challenges of Multiple Bond Dissociation with Full Configuration Interaction Quantum {{Monte Carlo}} Methods},
shorttitle = {Breaking the Carbon Dimer},
author = {Booth, George H. and Cleland, Deidre and Thom, Alex J. W. and Alavi, Ali},
title = {Quadratically Convergent Algorithm for Orbital Optimization in the Orbital-Optimized Coupled-Cluster Doubles Method and in Orbital-Optimized Second-Order {{M\o ller-Plesset}} Perturbation Theory},
author = {Bozkaya, U{\u g}ur and Turney, Justin M. and Yamaguchi, Yukio and Schaefer, Henry F. and Sherrill, C. David},
title = {Applicability of Multi-Reference Double-Excitation Ci (Mrd-Ci) Method to Calculation of Electronic Wavefunctions and Comparison with Related Techniques},
author = {Buenker, Rj and Peyerimhoff, Sd and Butscher, W},
title = {Spin Density Distribution in Open-Shell Transition Metal Systems: {{A}} Comparative {{Post-Hartree}}\textendash{{Fock}}, Density Functional Theory, and Quantum Monte Carlo Study of the {{CuCl}}{$_2$} Molecule},
author = {Caffarel, Michel and Giner, Emmanuel and Scemama, Anthony and {Ram{\'i}rez-Sol{\'i}s}, Alejandro},
title = {The Density Matrix Renormalization Group in Quantum Chemistry},
author = {Chan, Garnet Kin-Lic and Sharma, Sandeep},
year = {2011},
journal = {Annu. Rev. Phys. Chem.},
volume = {62},
pages = {465--481},
doi = {10.1146/annurev-physchem-032210-103338},
abstract = {The density matrix renormalization group is a method that is useful for describing molecules that have strongly correlated electrons. Here we provide a pedagogical overview of the basic challenges of strong correlation, how the density matrix renormalization group works, a survey of its existing applications to molecular problems, and some thoughts on the future of the method.},
title = {Spin-Adapted Selected Configuration Interaction in a Determinant Basis},
author = {Chilkuri, Vijay Gopal and Applencourt, Thomas and Gasperich, Kevin and Loos, Pierre-Fran{\c c}ois and Scemama, Anthony},
year = {2021},
journal = {Adv. Quantum Chem.},
pages = {in press},
publisher = {{Academic Press}},
doi = {10.1016/bs.aiq.2021.04.001},
abstract = {Selected configuration interaction (SCI) methods, when complemented with a second-order perturbative correction, provide near full configuration interaction (FCI) quality energies with only a small fraction of the Slater determinants of the FCI space. However, a selection criterion based on determinants alone does not ensure a spin-pure wave function. In other words, such SCI wave functions are not eigenfunctions of the \^S2 operator. In many situations (bond breaking, magnetic system, excited state, etc.), having a spin-adapted wave function is essential for a quantitatively correct description of the system. Here, we propose an efficient algorithm which, given an arbitrary determinant space, generates all the missing Slater determinants allowing one to obtain spin-adapted wave functions while avoiding manipulations involving configuration state functions. For example, generating all the possible determinants with 6 spin-up and 6 spin-down electrons in 12 open shells takes 21 CPU cycles per generated Slater determinant. The selection is still done with individual determinants, and one can take advantage of the basis of configuration state functions in the diagonalization of the Hamiltonian to reduce the memory footprint significantly.},
title = {Response Functions from Fourier Component Variational Perturbation Theory Applied to a Time-Averaged Quasienergy},
author = {Christiansen, Ove and J{\o}rgensen, Poul and H{\"a}ttig, Christof},
year = {1998},
journal = {Int. J. Quantum Chem.},
volume = {68},
pages = {1--52},
doi = {10.1002/(SICI)1097-461X(1998)68:1<1::AID-QUA1>3.0.CO;2-Z},
abstract = {Abstract It is demonstrated that frequency-dependent response functions can conveniently be derived from the time-averaged quasienergy. The variational criteria for the quasienergy determines the time-evolution of the wave-function parameters and the time-averaged time-dependent Hellmann\textendash Feynman theorem allows an identification of response functions as derivatives of the quasienergy. The quasienergy therefore plays the same role as the usual energy in time-independent theory, and the same techniques can be used to obtain computationally tractable expressions for response properties, as for energy derivatives in time-independent theory. This includes the use of the variational Lagrangian technique for obtaining expressions for molecular properties in accord with the 2n+1 and 2n+2 rules. The derivation of frequency-dependent response properties becomes a simple extension of variational perturbation theory to a Fourier component variational perturbation theory. The generality and simplicity of this approach are illustrated by derivation of linear and higher-order response functions for both exact and approximate wave functions and for both variational and nonvariational wave functions. Examples of approximate models discussed in this article are coupled-cluster, self-consistent field, and second-order M\o ller\textendash Plesset perturbation theory. A discussion of symmetry properties of the response functions and their relation to molecular properties is also given, with special attention to the calculation of transition- and excited-state properties. 1998 John Wiley \& Sons, Inc. Int J Quant Chem 68: 1\textendash 52, 1998},
title = {On the {{Correlation Problem}} in {{Atomic}} and {{Molecular Systems}}. {{Calculation}} of {{Wavefunction Components}} in {{Ursell-Type Expansion Using Quantum-Field Theoretical Methods}}},
title = {The Equation-of-Motion Coupled-Cluster Method. {{Applications}} to Open- and Closed-Shell Reference States},
author = {Comeau, Donald C. and Bartlett, Rodney J.},
year = {1993},
journal = {Chem. Phys. Lett.},
volume = {207},
number = {4},
pages = {414--423},
doi = {10.1016/0009-2614(93)89023-B},
abstract = {The equation-of-motion coupled-cluster method (EOM-CCSD) and its quadratic CI (EOM-QCISD) variant for excited states have been implemented in the ACES II program system. Results for open- and closed-shell reference states are reported for Be, N2, CO, O2, and O3. The results show that EOM-CCSD and EOM-QCISD generally provide reliable results for electronic excitation energies, particularly when the excited state is dominated by single excitations.},
title = {The Dalton Quantum Chemistry Program System},
author = {Aidas, Kestutis and Angeli, Celestino and Bak, Keld L. and Bakken, Vebj{\o}rn and Bast, Radovan and Boman, Linus and Christiansen, Ove and Cimiraglia, Renzo and Coriani, Sonia and Dahle, P{\aa}l and Dalskov, Erik K. and Ekstr{\"o}m, Ulf and Enevoldsen, Thomas and Eriksen, Janus J. and Ettenhuber, Patrick and Fern{\'a}ndez, Berta and Ferrighi, Lara and Fliegl, Heike and Frediani, Luca and Hald, Kasper and Halkier, Asger and H{\"a}ttig, Christof and Heiberg, Hanne and Helgaker, Trygve and Hennum, Alf Christian and Hettema, Hinne and Hjerten{\ae}s, Eirik and H{\o}st, Stinne and H{\o}yvik, Ida-Marie and Iozzi, Maria Francesca and Jans{\'i}k, Branislav and Jensen, Hans J{\o}rgen Aa. and Jonsson, Dan and J{\o}rgensen, Poul and Kauczor, Joanna and Kirpekar, Sheela and Kj{\ae}rgaard, Thomas and Klopper, Wim and Knecht, Stefan and Kobayashi, Rika and Koch, Henrik and Kongsted, Jacob and Krapp, Andreas and Kristensen, Kasper and Ligabue, Andrea and Lutn{\ae}s, Ola B. and Melo, Juan I. and Mikkelsen, Kurt V. and Myhre, Rolf H. and Neiss, Christian and Nielsen, Christian B. and Norman, Patrick and Olsen, Jeppe and Olsen, J{\'o}gvan Magnus H. and Osted, Anders and Packer, Martin J. and Pawlowski, Filip and Pedersen, Thomas B. and Provasi, Patricio F. and Reine, Simen and Rinkevicius, Zilvinas and Ruden, Torgeir A. and Ruud, Kenneth and Rybkin, Vladimir V. and Sa{\l}ek, Pawel and Samson, Claire C. M. and {de Mer{\'a}s}, Alfredo S{\'a}nchez and Saue, Trond and Sauer, Stephan P. A. and Schimmelpfennig, Bernd and Sneskov, Kristian and Steindal, Arnfinn H. and {Sylvester-Hvid}, Kristian O. and Taylor, Peter R. and Teale, Andrew M. and Tellgren, Erik I. and Tew, David P. and Thorvaldsen, Andreas J. and Th{\o}gersen, Lea and Vahtras, Olav and Watson, Mark A. and Wilson, David J. D. and Ziolkowski, Marcin and {\AA}gren, Hans},
title = {Accurate Full Configuration Interaction Correlation Energy Estimates for Five- and Six-Membered Rings},
author = {Damour, Yann and V{\'e}ril, Micka{\"e}l and Kossoski, F{\'a}bris and Caffarel, Michel and Jacquemin, Denis and Scemama, Anthony and Loos, Pierre-Fran{\c c}ois},
title = {Communication: {{Approaching}} Ex- Act Quantum Chemistry by Cluster Analysis of Full Configuration Interaction Quan- Tum Monte Carlo Wave Functions},
author = {Deustua, J. E. and Magoulas, I. and Shen, J. and Piecuch, P.},
title = {The Algebraic Diagrammatic Construction Scheme for the Polarization Propagator for the Calculation of Excited States},
author = {Dreuw, Andreas and Wormit, Michael},
year = {2015},
journal = {WIREs Comput. Mol. Sci.},
volume = {5},
number = {1},
pages = {82--95},
doi = {10.1002/wcms.1206},
abstract = {The algebraic diagrammatic construction (ADC) scheme for the polarization propagator provides a series of ab initio methods for the calculation of excited states based on perturbation theory. In recent years, the second-order ADC(2) scheme has attracted attention in the computational chemistry community because of its reliable accuracy and reasonable computational effort in the calculation of predominantly singly excited states. Owing to their size-consistency, ADC methods are suited for the investigation of large molecules. In addition, their Hermitian structure and the availability of the intermediate state representation (ISR) allow for straightforward computation of excited-state properties. Recently, an efficient implementation of ADC(3) has been reported, and its high accuracy for typical valence excited states of organic chromophores has been demonstrated. In this review, the origin of ADC-based excited-state methods in propagator theory is described, and an intuitive route for the derivation of algebraic expressions via the ISR is outlined and comparison to other excited-state methods is made. Existing computer codes and implemented ADC variants are reviewed, but most importantly the accuracy and limits of different ADC schemes are critically examined. WIREs Comput Mol Sci 2015, 5:82\textendash 95. doi: 10.1002/wcms.1206 This article is categorized under: Structure and Mechanism {$>$} Molecular Structures Electronic Structure Theory {$>$} Ab Initio Electronic Structure Methods Theoretical and Physical Chemistry {$>$} Spectroscopy},
title = {Automerization Reaction of Cyclobutadiene and Its Barrier Height: {{An}} Ab Initio Benchmark Multireference Average-Quadratic Coupled Cluster Study},
shorttitle = {Automerization Reaction of Cyclobutadiene and Its Barrier Height},
author = {{Eckert-Maksi{\'c}}, Mirjana and Vazdar, Mario and Barbatti, Mario and Lischka, Hans and Maksi{\'c}, Zvonimir B.},
year = {2006},
month = aug,
journal = {J. Chem. Phys.},
volume = {125},
number = {6},
pages = {064310},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.2222366},
abstract = {The problem of the double bond flipping interconversion of the two equivalent ground state structures of cyclobutadiene (CBD) is addressed at the multireference average-quadratic coupled cluster level of theory, which is capable of optimizing the structural parameters of the ground, transition, and excited states on an equal footing. The barrier height involving both the electronic and zero-point vibrational energy contributions is 6.3kcalmol-16.3kcalmol-1{$<$}math display="inline" overflow="scroll" altimg="eq-00001.gif"{$><$}mrow{$><$}mn{$>$}6.3{$<$}/mn{$><$}mspace width="0.3em"{$><$}/mspace{$><$}mi{$>$}kcal{$<$}/mi{$><$}mspace width="0.2em"{$><$}/mspace{$><$}msup{$><$}mi{$>$}mol{$<$}/mi{$><$}mrow{$><$}mo{$>$}-{$<$}/mo{$><$}mn{$>$}1{$<$}/mn{$><$}/mrow{$><$}/msup{$><$}/mrow{$><$}/math{$>$}, which is higher than the best earlier theoretical estimate of 4.0kcalmol-14.0kcalmol-1{$<$}math display="inline" overflow="scroll" altimg="eq-00002.gif"{$><$}mrow{$><$}mn{$>$}4.0{$<$}/mn{$><$}mspace width="0.3em"{$><$}/mspace{$><$}mi{$>$}kcal{$<$}/mi{$><$}mspace width="0.2em"{$><$}/mspace{$><$}msup{$><$}mi{$>$}mol{$<$}/mi{$><$}mrow{$><$}mo{$>$}-{$<$}/mo{$><$}mn{$>$}1{$<$}/mn{$><$}/mrow{$><$}/msup{$><$}/mrow{$><$}/math{$>$}. This result is confirmed by including into the reference space the orbitals of the CC {$\sigma\sigma<$}math display="inline" overflow="scroll" altimg="eq-00003.gif"{$><$}mi{$>\sigma<$}/mi{$><$}/math{$>$} bonds beyond the standard {$\pi\pi<$}math display="inline" overflow="scroll" altimg="eq-00004.gif"{$><$}mi{$>\pi<$}/mi{$><$}/math{$>$} orbital space. It places the present value into the middle of the range of the measured data (1.6\textendash 10kcalmol-1)(1.6\textendash 10kcalmol-1){$<$}math display="inline" overflow="scroll" altimg="eq-00005.gif"{$><$}mrow{$><$}mo{$>$}({$<$}/mo{$><$}mn{$>$}1.6{$<$}/mn{$><$}mo{$>$}\textendash{$<$}/mo{$><$}mn{$>$}10{$<$}/mn{$><$}mspace width="0.3em"{$><$}/mspace{$><$}mi{$>$}kcal{$<$}/mi{$><$}mspace width="0.2em"{$><$}/mspace{$><$}msup{$><$}mi{$>$}mol{$<$}/mi{$><$}mrow{$><$}mo{$>$}-{$<$}/mo{$><$}mn{$>$}1{$<$}/mn{$><$}/mrow{$><$}/msup{$><$}mo{$>$}){$<$}/mo{$><$}/mrow{$><$}/math{$>$}. An adiabatic singlet-triplet energy gap of 7.4kcalmol-17.4kcalmol-1{$<$}math display="inline" overflow="scroll" altimg="eq-00006.gif"{$><$}mrow{$><$}mn{$>$}7.4{$<$}/mn{$><$}mspace width="0.3em"{$><$}/mspace{$><$}mi{$>$}kcal{$<$}/mi{$><$}mspace width="0.2em"{$><$}/mspace{$><$}msup{$><$}mi{$>$}mol{$<$}/mi{$><$}mrow{$><$}mo{$>$}-{$<$}/mo{$><$}mn{$>$}1{$<$}/mn{$><$}/mrow{$><$}/msup{$><$}/mrow{$><$}/math{$>$} between the transition state Btg1Btg1{$<$}math display="inline" overflow="scroll" altimg="eq-00007.gif"{$><$}mmultiscripts{$><$}mi{$>$}B{$<$}/mi{$><$}mrow{$><$}mi{$>$}t{$<$}/mi{$><$}mi{$>$}g{$<$}/mi{$><$}/mrow{$><$}none{$><$}/none{$><$}mprescripts{$><$}/mprescripts{$><$}none{$><$}/none{$><$}mn{$>$}1{$<$}/mn{$><$}/mmultiscripts{$><$}/math{$>$} and the first triplet A2g3A2g3{$<$}math display="inline" overflow="scroll" altimg="eq-00008.gif"{$><$}mmultiscripts{$><$}mi{$>$}A{$<$}/mi{$><$}mrow{$><$}mn{$>$}2{$<$}/mn{$><$}mi{$>$}g{$<$}/mi{$><$}/mrow{$><$}none{$><$}/none{$><$}mprescripts{$><$}/mprescripts{$><$}none{$><$}/none{$><$}mn{$>$}3{$<$}/mn{$><$}/mmultiscripts{$><$}/math{$>$} state is obtained. A low barrier height for the CBD automerization and a small {$\Delta$}E(A2g3,B1g1){$\Delta$}E(A2g3,B1g1){$<$}math display="inline" overflow="scroll" altimg="eq-00009.gif"{$><$}mrow{$><$}mi{$>\Delta<$}/mi{$><$}mi{$>$}E{$<$}/mi{$><$}mrow{$><$}mo{$>$}({$<$}/mo{$><$}mmultiscripts{$><$}mi{$>$}A{$<$}/mi{$><$}mrow{$><$}mn{$>$}2{$<$}/mn{$><$}mi{$>$}g{$<$}/mi{$><$}/mrow{$><$}none{$><$}/none{$><$}mprescripts{$><$}/mprescripts{$><$}none{$><$}/none{$><$}mn{$>$}3{$<$}/mn{$><$}/mmultiscripts{$><$}mo{$>$},{$<$}/mo{$><$}mmultiscripts{$><$}mi{$>$}B{$<$}/mi{$><$}mrow{$><$}mn{$>$}1{$<$}/mn{$><$}mi{$>$}g{$<$}/mi{$><$}/mrow{$><$}none{$><$}/none{$><$}mprescripts{$><$}/mprescripts{$><$}none{$><$}/none{$><$}mn{$>$}1{$<$}/mn{$><$}/mmultiscripts{$><$}mo{$>$}){$<$}/mo{$><$}/mrow{$><$}/mrow{$><$}/math{$>$} gap bear some relevanc
title = {An Extension of the Coupled Cluster Formalism to Excited States ({{I}})},
author = {Emrich, K.},
year = {1981},
journal = {Nuc. Phys. A},
volume = {351},
number = {3},
pages = {379--396},
doi = {10.1016/0375-9474(81)90179-2},
abstract = {The expS method (coupled cluster formalism) is extended to excited states of finite and infinite systems. We obtain equations which are formally similar to the known ground-state equations of the expS theory. The method is applicable to Fermi as well as Bose systems.},
title = {The Ground State Electronic Energy of Benzene},
author = {Eriksen, Janus J. and Anderson, Tyler A. and Deustua, J. Emiliano and Ghanem, Khaldoon and Hait, Diptarka and Hoffmann, Mark R. and Lee, Seunghoon and Levine, Daniel S. and Magoulas, Ilias and Shen, Jun and Tubman, Norman M. and Whaley, K. Birgitta and Xu, Enhua and Yao, Yuan and Zhang, Ning and Alavi, Ali and Chan, Garnet Kin-Lic and {Head-Gordon}, Martin and Liu, Wenjian and Piecuch, Piotr and Sharma, Sandeep and {Ten-no}, Seiichiro L. and Umrigar, C. J. and Gauss, J{\"u}rgen},
title = {Three {{Arguments Supporting}} a {{Rectangular Structure}} for {{Tetra-tert-butylcyclobutadiene}}},
author = {Ermer, Otto and Heilbronner, Edgar},
year = {1983},
journal = {Angew. Chem. Int. Ed. Engl.},
volume = {22},
number = {5},
pages = {402--403},
issn = {1521-3773},
doi = {10.1002/anie.198304021},
copyright = {Copyright \textcopyright{} 1983 by Verlag Chemie, GmbH, Germany},
date-modified = {2022-03-23 11:50:57 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/NZGUUR4K/Ermer et Heilbronner - 1983 - Three Arguments Supporting a Rectangular Structure.pdf;/Users/monino/Zotero/storage/FEX6ABAS/anie.html}
title = {The {{Nature}} of the {{Singlet}} and {{Triplet States}} of {{Cyclobutadiene}} as {{Revealed}} by {{Quantum Interference}}},
author = {Fantuzzi, Felipe and Cardozo, Thiago M. and Nascimento, Marco A. C.},
year = {2016},
journal = {ChemPhysChem},
volume = {17},
number = {2},
pages = {288--295},
issn = {1439-7641},
doi = {10.1002/cphc.201500885},
abstract = {The generalized product function energy partitioning (GPF-EP) method is applied to the description of the cyclobutadiene molecule. The GPF wave function was built to reproduce generalized valence bond (GVB) and spin-coupled (SC) wave functions. The influence of quasiclassical and quantum interference contributions to each chemical bond of the system are analyzed along the automerization reaction coordinate for the lowest singlet and triplet states. The results show that the interference effect on the {$\pi$} space reduces the electronic energy of the singlet cyclobutadiene relative to the second-order Jahn\textendash Teller distortion, which takes the molecule from a D4h to a D2h structure. Our results also suggest that the {$\pi$} space of the 1B1g state of the square cyclobutadiene is composed of a weak four center\textendash four electron bond, whereas the 3A2g state has a four center\textendash two electron {$\pi$} bond. Finally, we also show that, although strain effects are nonnegligible, the thermodynamics of the main decomposition pathway of cyclobutadiene in the gas phase is dominated by the {$\pi$} space interference.},
date-modified = {2022-03-23 11:51:02 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/XMXT7B6P/Fantuzzi et al. - 2016 - The Nature of the Singlet and Triplet States of Cy.pdf;/Users/monino/Zotero/storage/AJRDDU3I/cphc.html}
author = {Frisch, M. J. and Trucks, G. W. and Schlegel, H. B. and Scuseria, G. E. and Robb, M. A. and Cheeseman, J. R. and Scalmani, G. and Barone, V. and Mennucci, B. and Petersson, G. A. and Nakatsuji, H. and Caricato, M. and Li, X. and Hratchian, H. P. and Izmaylov, A. F. and Bloino, J. and Zheng, G. and Sonnenberg, J. L. and Hada, M. and Ehara, M. and Toyota, K. and Fukuda, R. and Hasegawa, J. and Ishida, M. and Nakajima, T. and Honda, Y. and Kitao, O. and Nakai, H. and Vreven, T. and Montgomery, Jr., J. A. and Peralta, J. E. and Ogliaro, F. and Bearpark, M. and Heyd, J. J. and Brothers, E. and Kudin, K. N. and Staroverov, V. N. and Kobayashi, R. and Normand, J. and Raghavachari, K. and Rendell, A. and Burant, J. C. and Iyengar, S. S. and Tomasi, J. and Cossi, M. and Rega, N. and Millam, J. M. and Klene, M. and Knox, J. E. and Cross, J. B. and Bakken, V. and Adamo, C. and Jaramillo, J. and Gomperts, R. and Stratmann, R. E. and Yazyev, O. and Austin, A. J. and Cammi, R. and Pomelli, C. and Ochterski, J. W. and Martin, R. L. and Morokuma, K. and Zakrzewski, V. G. and Voth, G. A. and Salvador, P. and Dannenberg, J. J. and Dapprich, S. and Daniels, A. D. and Farkas, {\"O}. and Foresman, J. B. and Ortiz, J. V. and Cioslowski, J. and Fox, D. J.},
title = {Recent Developments in the General Atomic and Molecular Electronic Structure System},
author = {Barca, Giuseppe M. J. and Bertoni, Colleen and Carrington, Laura and Datta, Dipayan and De Silva, Nuwan and Deustua, J. Emiliano and Fedorov, Dmitri G. and Gour, Jeffrey R. and Gunina, Anastasia O. and Guidez, Emilie and Harville, Taylor and Irle, Stephan and Ivanic, Joe and Kowalski, Karol and Leang, Sarom S. and Li, Hui and Li, Wei and Lutz, Jesse J. and Magoulas, Ilias and Mato, Joani and Mironov, Vladimir and Nakata, Hiroya and Pham, Buu Q. and Piecuch, Piotr and Poole, David and Pruitt, Spencer R. and Rendell, Alistair P. and Roskop, Luke B. and Ruedenberg, Klaus and Sattasathuchana, Tosaporn and Schmidt, Michael W. and Shen, Jun and Slipchenko, Lyudmila and Sosonkina, Masha and Sundriyal, Vaibhav and Tiwari, Ananta and Galvez Vallejo, Jorge L. and Westheimer, Bryce and Wloch, Marta and Xu, Peng and Zahariev, Federico and Gordon, Mark S.},
title = {Quantum Package 2.0: {{An}} Open-Source Determinant-Driven Suite of Programs},
author = {Garniron, Yann and Applencourt, Thomas and Gasperich, Kevin and Benali, Anouar and Fert{\'e}, Anthony and Paquier, Julien and Pradines, Barth{\'e}l{\'e}my and Assaraf, Roland and Reinhardt, Peter and Toulouse, Julien and Barbaresco, Pierrette and Renon, Nicolas and David, Gr{\'e}goire and Malrieu, Jean-Paul and V{\'e}ril, Micka{\"e}l and Caffarel, Michel and Loos, Pierre-Fran{\c c}ois and Giner, Emmanuel and Scemama, Anthony},
title = {A Modified Definition of the Zeroth-Order Hamiltonian in Multiconfigurational Perturbation Theory ({{CASPT2}})},
author = {Ghigo, Giovanni and Roos, Bj{\"o}rn O. and Malmqvist, Per-{\AA}ke},
year = {2004},
journal = {Chem. Phys. Lett.},
volume = {396},
number = {1},
pages = {142--149},
issn = {0009-2614},
doi = {10.1016/j.cplett.2004.08.032},
abstract = {A new shifted zeroth-order Hamiltonian is presented, which will be used in second-order multiconfigurational perturbation theory (CASPT2). The new approximation corrects for the systematic error of the original formulation, which led to an relative overestimate of the correlation energy for open shell system, resulting in too small dissociation and excitation energies. Errors in the De values for 49 diatomic molecules have been reduced with more than 50\%. Calculations on excited states of the N2 and benzene molecules give a similar improvement.},
title = {Fixed-Node Diffusion {{Monte Carlo}} Potential Energy Curve of the Fluorine Molecule {{F2}} Using Selected Configuration Interaction Trial Wavefunctions},
author = {Giner, Emmanuel and Scemama, Anthony and Caffarel, Michel},
title = {The Third-Order Algebraic Diagrammatic Construction Method ({{ADC}}(3)) for the Polarization Propagator for Closed-Shell Molecules: {{Efficient}} Implementation and Benchmarking},
shorttitle = {The Third-Order Algebraic Diagrammatic Construction Method ({{ADC}}(3)) for the Polarization Propagator for Closed-Shell Molecules},
author = {Harbach, Philipp H. P. and Wormit, Michael and Dreuw, Andreas},
year = {2014},
month = aug,
journal = {J. Chem. Phys.},
volume = {141},
number = {6},
pages = {064113},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.4892418},
abstract = {The implementation of an efficient program of the algebraic diagrammatic construction method for the polarisation propagator in third-order perturbation theory (ADC(3)) for the computation of excited states is reported. The accuracies of ADC(2) and ADC(3) schemes have been investigated with respect to Thiel's recently established benchmark set for excitation energies and oscillator strengths. The calculation of 141 vertical excited singlet and 71 triplet states of 28 small to medium-sized organic molecules has revealed that ADC(3) exhibits mean error and standard deviation of 0.12 {$\pm$} 0.28 eV for singlet states and -0.18 {$\pm$} 0.16 eV for triplet states when the provided theoretical best estimates are used as benchmark. Accordingly, the ADC(2)-s and ADC(2)-x calculations revealed accuracies of 0.22 {$\pm$} 0.38 eV and -0.70 {$\pm$} 0.37 eV for singlets and 0.12 {$\pm$} 0.16 eV and -0.55 {$\pm$} 0.20 eV for triplets, respectively. For a comparison of CC3 and ADC(3), only non-CC3 benchmark values were considered, which comprise 84 singlet states and 19 triplet states. For these singlet states CC3 exhibits an accuracy of 0.23 {$\pm$} 0.21 eV and ADC(3) an accuracy of 0.08 {$\pm$} 0.27 eV, and accordingly for the triplet states of 0.12 {$\pm$} 0.10 eV and -0.10 {$\pm$} 0.13 eV, respectively. Hence, based on the quality of the existing benchmark set it is practically not possible to judge whether ADC(3) or CC3 is more accurate, however, ADC(3) has a much larger range of applicability due to its more favourable scaling of O(N6) with system size.},
date-modified = {2022-03-23 11:51:20 +0100},
file = {/Users/monino/Zotero/storage/C6KCZ58W/Harbach et al. - 2014 - The third-order algebraic diagrammatic constructio.pdf}
title = {Time-Dependent Density Functional Theory within the {{Tamm}}\textendash{{Dancoff}} Approximation},
author = {Hirata, So and {Head-Gordon}, Martin},
year = {1999},
journal = {Chem. Phys. Lett.},
volume = {314},
number = {3},
pages = {291--299},
doi = {10.1016/S0009-2614(99)01149-5},
abstract = {A computationally simple method for molecular excited states, namely, the Tamm\textendash Dancoff approximation to time-dependent density functional theory, is proposed and implemented. This method yields excitation energies for several closed- and open-shell molecules that are essentially of the same quality as those obtained from time-dependent density functional theory itself, when the same exchange-correlation functional is used.},
title = {Assessment of Noncollinear Spin-Flip {{Tamm}}\textendash{{Dancoff}} Approximation Time-Dependent Density-Functional Theory for the Photochemical Ring-Opening of Oxirane},
author = {{Huix-Rotllant}, Miquel and Natarajan, Bhaarathi and Ipatov, Andrei and Muhavini Wawire, C. and Deutsch, Thierry and Casida, Mark E.},
title = {Bonding {{Electron Density Distribution}} in {{Tetra-tert-butylcyclobutadiene}}\textemdash{} {{A Molecule}} with an {{Obviously Non-Square Four-Membered}} Ring},
author = {Irngartinger, Hermann and Nixdorf, Matthias},
year = {1983},
journal = {Angew. Chem. Int. Ed. Engl.},
volume = {22},
number = {5},
pages = {403--404},
issn = {1521-3773},
doi = {10.1002/anie.198304031},
copyright = {Copyright \textcopyright{} 1983 by Verlag Chemie, GmbH, Germany},
date-modified = {2022-03-23 11:51:31 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/LVYXNTRH/Irngartinger et Nixdorf - 1983 - Bonding Electron Density Distribution in Tetra-ter.pdf;/Users/monino/Zotero/storage/5QS87AEI/anie.html}
title = {Calculation of Frequency-Dependent Polarizabilities Using General Coupled-Cluster Models},
author = {K{\'a}llay, Mih{\'a}ly and Gauss, J{\"u}rgen},
year = {2006},
journal = {J. Mol. Struct. THEOCHEM},
volume = {768},
number = {1},
pages = {71--77},
doi = {10.1016/j.theochem.2006.05.021},
abstract = {An analytic scheme for the calculation of frequency-dependent polarizabilities within a response-theory approach has been implemented for the use within general coupled-cluster (CC) models with arbitrary excitations in the cluster operator. Calculations for CH+ and CN demonstrate the fast convergence of the coupled-cluster approach when successively higher excitations are considered. Quadruple excitation effects on the frequency-dependent polarizabilities are found to be rather small except close to the poles.},
title = {Ground- and {{Excited-State Aromaticity}} and {{Antiaromaticity}} in {{Benzene}} and {{Cyclobutadiene}}},
author = {Karadakov, Peter B.},
year = {2008},
month = aug,
journal = {J. Phys. Chem. A},
volume = {112},
number = {31},
pages = {7303--7309},
publisher = {{American Chemical Society}},
issn = {1089-5639},
doi = {10.1021/jp8037335},
abstract = {The aromaticity and antiaromaticity of the ground state (S0), lowest triplet state (T1), and first singlet excited state (S1) of benzene, and the ground states (S0), lowest triplet states (T1), and the first and second singlet excited states (S1 and S2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S0 state of benzene, the T1 and S1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T1 and S1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T1 state of rectangular cyclobutadiene is still aromatic, but the S1 state is antiaromatic, just as the S2 state of square cyclobutadiene; the S2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known ``triplet aromaticity'' of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.},
date-modified = {2022-03-23 11:51:41 +0100},
file = {/Users/monino/Zotero/storage/MAYI58IW/Karadakov - 2008 - Ground- and Excited-State Aromaticity and Antiarom.pdf;/Users/monino/Zotero/storage/65C9P8RP/jp8037335.html}
}
@incollection{Klessinger_1995,
title = {Excited States and Photochemistry of Organic Molecules},
title = {Excitation Energies from the Coupled Cluster Singles and Doubles Linear Response Function ({{CCSDLR}}). {{Applications}} to {{Be}}, {{CH}} {$^+$} , {{CO}}, and {{H}} {$_2$} {{O}}},
author = {Koch, Henrik and Jensen, Hans Jorgen Aa. and Jorgensen, Poul and Helgaker, Trygve},
title = {Excitation Energies of {{BH}}, {{CH2}} and {{Ne}} in Full Configuration Interaction and the Hierarchy {{CCS}}, {{CC2}}, {{CCSD}} and {{CC3}} of Coupled Cluster Models},
author = {Koch, Henrik and Christiansen, Ove and J{\o}rgensen, Poul and Olsen, Jeppe},
year = {1995},
month = sep,
journal = {Chem. Phys. Lett.},
volume = {244},
number = {1},
pages = {75--82},
issn = {0009-2614},
doi = {10.1016/0009-2614(95)00914-P},
abstract = {Excitation energies in the coupled cluster model hierarchy CCS, CC2, CCSD and CC3 have been calculated for Ne, BH and CH2 and compared with full configuration interaction (FCI) results. Single replacement dominated excitations are improved at each level in this hierarchy, with a decrease in the error compared to FCI of about a factor of three at each level. This decrease is in accordance with the fact that the single replacement dominated excitations in CCS, CC2, CCSD and CC3 are correct through respectively first, second and third order in the fluctuation potential. The improvement from CC2 to CCSD is due to the fact that CCSD gives a full coupled cluster treatment in the singles, doubles space. Double replacement dominated excitations can only be described at the CCSD and CC3 levels, and are correct through first and second order, respectively. The CC3 double replacement dominated excitations have similar quality as the single replacement dominated excitations in CC2. The scaling of CCS, CC2, CCSD and CC3 is N4, N5, N6 and N7, respectively, where N is the number of orbitals.},
date-modified = {2022-03-23 11:51:44 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/HWJJKRFE/Koch et al. - 1995 - Excitation energies of BH, CH2 and Ne in full conf.pdf;/Users/monino/Zotero/storage/6JPTSDU6/000926149500914P.html}
title = {State-Specific Multireference Coupled-Cluster Theory},
author = {K{\"o}hn, Andreas and Hanauer, Matthias and M{\"u}ck, Leonie Anna and Jagau, Thomas-Christian and Gauss, J{\"u}rgen},
year = {2013},
journal = {WIREs Comput. Mol. Sci.},
volume = {3},
number = {2},
pages = {176--197},
doi = {10.1002/wcms.1120},
abstract = {Abstract The multireference problem is considered one of the great challenges in coupled-cluster (CC) theory. Most recent developments are based on state-specific approaches, which focus on a single state and avoid some of the numerical problems of more general approaches. We review various state-of-the-art methods, including Mukherjee's state-specific multireference coupled-cluster (Mk-MRCC) theory, multireference Brillouin\textendash Wigner coupled-cluster (MR-BWCC) theory, the MRexpT method, and internally contracted multireference coupled-cluster (ic-MRCC) theory. Related methods such as extended single-reference schemes [e.g., the complete active space coupled-cluster (CASCC) theory] and canonical transformation (CT) theory are covered as well. The comparison is done on the basis of formal arguments, implementation issues, and numerical results. Although a final and generally accepted multireference CC theory is still lacking, it is emphasized that recent developments render the new MRCC schemes useful tools for solving chemical problems. 2012 John Wiley \& Sons, Ltd. This article is categorized under: Electronic Structure Theory \textquestiondown{} Ab Initio Electronic Structure Methods},
title = {Spectroscopic {{Observation}} of the {{Triplet Diradical State}} of a {{Cyclobutadiene}}},
author = {Kostenko, Arseni and Tumanskii, Boris and Kobayashi, Yuzuru and Nakamoto, Masaaki and Sekiguchi, Akira and Apeloig, Yitzhak},
year = {2017},
journal = {Angew. Chem. Int. Ed.},
volume = {56},
number = {34},
pages = {10183--10187},
issn = {1521-3773},
doi = {10.1002/anie.201705228},
abstract = {Tetrakis(trimethylsilyl)cyclobuta-1,3-diene (1) was subjected to a temperature-dependent EPR study to allow the first spectroscopic observation of a triplet diradical state of a cyclobutadiene (2). From the temperature dependent EPR absorption area we derive a singlet\textrightarrow triplet (1\textrightarrow 2) energy gap, EST, of 13.9 kcal mol-1, in agreement with calculated values. The zero-field splitting parameters D=0.171 cm-1, E=0 cm-1 are accurately reproduced by DFT calculations. The triplet diradical 2 is thermally accessible at moderate temperatures. It is not an intermediate in the thermal cycloreversion of cyclobutadiene to two acetylene molecules.},
title = {The Method of Moments of Coupled-Cluster Equations and the Renormalized {{CCSD}}[{{T}}], {{CCSD}}({{T}}), {{CCSD}}({{TQ}}), and {{CCSDT}}({{Q}}) Approaches},
title = {Uv Photoelectron Spectrum of Cyclobutadiene. {{Free}} Cyclobutadiene Stable up to High Temperatures},
author = {Kreile, J{\"u}rgen and M{\"u}nzel, Norbert and Schweig, Armin and Specht, Harald},
year = {1986},
month = feb,
journal = {Chem. Phys. Lett.},
volume = {124},
number = {2},
pages = {140--146},
issn = {0009-2614},
doi = {10.1016/0009-2614(86)85133-8},
abstract = {The Hel photoelectron spectrum of cyclobutadiene (CB) has been obtained under conditions which demonstrate that free CB is stable up to temperatures of several hundred \textdegree C. A new experimental argument for the rectangular geometry of CB is presented. Shake-up structures are unimportant for the interpretation of the PE spectrum of CB. LNDO/S PERTCI, MNDO PERTCI and previous experimental vertical ionization energy estimates accord with the experimental data.},
date-modified = {2022-03-23 11:51:52 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/S3GSHKPE/Kreile et al. - 1986 - Uv photoelectron spectrum of cyclobutadiene. free .pdf;/Users/monino/Zotero/storage/SWP7NVNH/0009261486851338.html}
title = {Size-Consistent Wave Functions for Bond-Breaking: The Equation-of-Motion Spin-Flip Model},
author = {Krylov, Anna I.},
year = {2001},
journal = {Chem. Phys. Lett.},
volume = {338},
number = {4},
pages = {375--384},
issn = {0009-2614},
doi = {10.1016/S0009-2614(01)00287-1},
abstract = {A new approach to the bond-breaking problem is proposed. Both closed and open shell singlet states are described within a single reference formalism as spin-flipping, e.g., {$\alpha\rightarrow\beta$}, excitations from a triplet (Ms=1) reference state for which both dynamical and non-dynamical correlation effects are much smaller than for the corresponding singlet state. Formally, the new theory can be viewed as an equation-of-motion (EOM) model where excited states are sought in the basis of determinants conserving the total number of electrons but changing the number of {$\alpha$} and {$\beta$} electrons. The results for two simplest members of the proposed hierarchy of approximations are presented.},
title = {Perturbative Corrections to the Equation-of-Motion Spin\textendash Flip Self-Consistent Field Model: {{Application}} to Bond-Breaking and Equilibrium Properties of Diradicals},
author = {Krylov, Anna I. and Sherrill, C. David},
title = {Spin-Flip Equation-of-Motion Coupled-Cluster Electronic Structure Method for a Description of Excited States, Bond Breaking, Diradicals, and Triradicals},
title = {Equation-of-Motion Coupled-Cluster Methods for Open-Shell and Electronically Excited Species: {{The}} Hitchhiker's Guide to Fock Space},
author = {Krylov, Anna I.},
year = {2008},
journal = {Annu. Rev. Phys. Chem.},
volume = {59},
number = {1},
pages = {433--462},
doi = {10.1146/annurev.physchem.59.032607.093602},
abstract = {The equation-of-motion coupled-cluster (EOM-CC) approach is a versatile electronic-structure tool that allows one to describe a variety of multiconfigurational wave functions within single-reference formalism. This review provides a guide to established EOM methods illustrated by examples that demonstrate the types of target states currently accessible by EOM. It focuses on applications of EOM-CC to electronically excited and open-shell species. The examples emphasize EOM's advantages for selected situations often perceived as multireference cases [e.g., interacting states of different nature, Jahn-Teller (JT) and pseudo-JT states, dense manifolds of ionized states, diradicals, and triradicals]. I also discuss limitations and caveats and offer practical solutions to some problematic situations. The review also touches on some formal aspects of the theory and important current developments.},
title = {Recursive Intermediate Factorization and Complete Computational Linearization of the Coupled-Cluster Single, Double, Triple, and Quadruple Excitation Equations},
author = {Kucharski, Stanislaw A. and Bartlett, Rodney J.},
year = {1991},
month = jul,
journal = {Theoret. Chim. Acta},
volume = {80},
number = {4},
pages = {387--405},
issn = {1432-2234},
doi = {10.1007/BF01117419},
abstract = {The nonlinear CCSDTQ equations are written in a fully linearized form, via the introduction of computationally convenient intermediates. An efficient formulation of the coupled cluster method is proposed. Due to a recursive method for the calculation of intermediates, all computational steps involve the multiplication of an intermediate with aT vertex. This property makes it possible to express the CC equations exclusively in terms of matrix products which can be directly transformed into a highly vectorized program.},
date-modified = {2022-03-23 11:51:57 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/XF724XDM/Kucharski et Bartlett - 1991 - Recursive intermediate factorization and complete .pdf}
title = {Recursive Intermediate Factorization and Complete Computational Linearization of the Coupled-Cluster Single, Double, Triple, and Quadruple Excitation Equations},
author = {Kucharski, Stanislaw A. and Bartlett, Rodney J.},
year = {1991},
month = jul,
journal = {Theoret. Chim. Acta},
volume = {80},
number = {4},
pages = {387--405},
issn = {1432-2234},
doi = {10.1007/BF01117419},
abstract = {The nonlinear CCSDTQ equations are written in a fully linearized form, via the introduction of computationally convenient intermediates. An efficient formulation of the coupled cluster method is proposed. Due to a recursive method for the calculation of intermediates, all computational steps involve the multiplication of an intermediate with aT vertex. This property makes it possible to express the CC equations exclusively in terms of matrix products which can be directly transformed into a highly vectorized program.},
langid = {english},
file = {/Users/monino/Zotero/storage/DMNAXLAZ/Kucharski et Bartlett - 1991 - Recursive intermediate factorization and complete .pdf}
title = {Coupled-Cluster Theory for Excited Electronic States: {{The}} Full Equation-of-Motion Coupled-Cluster Single, Double, and Triple Excitation Method},
author = {Kucharski, Stanis{\l}aw A. and W{\l}och, Marta and Musia{\l}, Monika and Bartlett, Rodney J.},
title = {Solutions of the Two-Dimensional Hubbard Model: Benchmarks and Results from a Wide Range of Numerical Algorithms},
author = {LeBlanc, J. P. F. and Antipov, Andrey E and Becca, Federico and Bulik, Ireneusz W and Chan, Garnet Kin-Lic and Chung, Chia-Min and Deng, Youjin and Ferrero, Michel and Henderson, Thomas M and {Jim{\'e}nez-Hoyos}, Carlos A and others},
title = {Development of the {{Colle-Salvetti}} Correlation-Energy Formula into a Functional of the Electron Density},
author = {Lee, Chengteh and Yang, Weitao and Parr, Robert G.},
year = {1988},
month = jan,
journal = {Phys. Rev. B},
volume = {37},
number = {2},
pages = {785--789},
publisher = {{American Physical Society}},
doi = {10.1103/PhysRevB.37.785},
abstract = {A correlation-energy formula due to Colle and Salvetti [Theor. Chim. Acta 37, 329 (1975)], in which the correlation energy density is expressed in terms of the electron density and a Laplacian of the second-order Hartree-Fock density matrix, is restated as a formula involving the density and local kinetic-energy density. On insertion of gradient expansions for the local kinetic-energy density, density-functional formulas for the correlation energy and correlation potential are then obtained. Through numerical calculations on a number of atoms, positive ions, and molecules, of both open- and closed-shell type, it is demonstrated that these formulas, like the original Colle-Salvetti formulas, give correlation energies within a few percent., This article appears in the following collection:},
date-modified = {2022-03-23 11:49:50 +0100},
file = {/Users/monino/Zotero/storage/TMNNDIWU/Lee et al. - 1988 - Development of the Colle-Salvetti correlation-ener.pdf;/Users/monino/Zotero/storage/M8BYQK3D/PhysRevB.37.html}
title = {Eliminating Spin-Contamination of Spin-Flip Time Dependent Density Functional Theory within Linear Response Formalism by the Use of Zeroth-Order Mixed-Reference ({{MR}}) Reduced Density Matrix},
author = {Lee, Seunghoon and Filatov, Michael and Lee, Sangyoub and Choi, Cheol Ho},
title = {Externally Corrected {{CCSD}} with Renormalized Perturbative Triples (r-Ecccsd(t)) and the Density Matrix Renormalization Group and Selected Configuration Interaction External Sources},
author = {Lee, Seunghoon and Zhai, Huanchen and Sharma, Sandeep and Umrigar, C. J. and Chan, Garnet Kin-Lic},
title = {Adapting Algebraic Diagrammatic Construction Schemes for the Polarization Propagator to Problems with Multi-Reference Electronic Ground States Exploiting the Spin-Flip Ansatz},
author = {Lefrancois, Daniel and Wormit, Michael and Dreuw, Andreas},
year = {2015},
month = sep,
journal = {J. Chem. Phys.},
volume = {143},
number = {12},
pages = {124107},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.4931653},
abstract = {For the investigation of molecular systems with electronic ground states exhibiting multi-reference character, a spin-flip (SF) version of the algebraic diagrammatic construction (ADC) scheme for the polarization propagator up to third order perturbation theory (SF-ADC(3)) is derived via the intermediate state representation and implemented into our existing ADC computer program adcman. The accuracy of these new SF-ADC(n) approaches is tested on typical situations, in which the ground state acquires multi-reference character, like bond breaking of H2 and HF, the torsional motion of ethylene, and the excited states of rectangular and square-planar cyclobutadiene. Overall, the results of SF-ADC(n) reveal an accurate description of these systems in comparison with standard multi-reference methods. Thus, the spin-flip versions of ADC are easy-to-use methods for the calculation of ``few-reference'' systems, which possess a stable single-reference triplet ground state.},
date-modified = {2022-03-23 11:52:02 +0100},
file = {/Users/monino/Zotero/storage/HIV3CENN/Lefrancois et al. - 2015 - Adapting algebraic diagrammatic construction schem.pdf}
title = {Accounting for the Exact Degeneracy and Quasidegeneracy in the Automerization of Cyclobutadiene via Multireference Coupled-Cluster Methods},
author = {Li, Xiangzhu and Paldus, Josef},
year = {2009},
month = sep,
journal = {J. Chem. Phys.},
volume = {131},
number = {11},
pages = {114103},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.3225203},
abstract = {The automerization of cyclobutadiene (CBD) is employed to test the performance of the reduced multireference (RMR) coupled-cluster (CC) method with singles and doubles (RMR CCSD) that employs a modest-size MR CISD wave function as an external source for the most important (primary) triples and quadruples in order to account for the nondynamic correlation effects in the presence of quasidegeneracy, as well as of its perturbatively corrected version accounting for the remaining (secondary) triples [RMR CCSD(T)]. The experimental results are compared with those obtained by the standard CCSD and CCSD(T) methods, by the state universal (SU) MR CCSD and its state selective or state specific (SS) version as formulated by Mukherjee et al. (SS MRCC or MkMRCC) and, wherever available, by the Brillouin\textendash Wigner MRCC [MR BWCCSD(T)] method. Both restricted Hartree-Fock (RHF) and multiconfigurational self-consistent field (MCSCF) molecular orbitals are employed. For a smaller STO-3G basis set we also make a comparison with the exact full configuration interaction (FCI) results. Both fundamental vibrational energies\textemdash as obtained via the integral averaging method (IAM) that can handle anomalous potentials and automatically accounts for anharmonicity\textendash{} and the CBD automerization barrier for the interconversion of the two rectangular structures are considered. It is shown that the RMR CCSD(T) potential has the smallest nonparallelism error relative to the FCI potential and the corresponding fundamental vibrational frequencies compare reasonably well with the experimental ones and are very close to those recently obtained by other authors. The effect of anharmonicity is assessed using the second-order perturbation theory (MP2). Finally, the invariance of the RMR CC methods with respect to orbital rotations is also examined.},
date-modified = {2022-03-23 11:50:03 +0100},
file = {/Users/monino/Zotero/storage/BXVNKPMI/Li et Paldus - 2009 - Accounting for the exact degeneracy and quasidegen.pdf}
title = {Reference Dependence of the Two-Determinant Coupled-Cluster Method for Triplet and Open-Shell Singlet States of Biradical Molecules},
author = {Lutz, Jesse J. and Nooijen, Marcel and Perera, Ajith and Bartlett, Rodney J.},
year = {2018},
month = apr,
journal = {J. Chem. Phys.},
volume = {148},
number = {16},
pages = {164102},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.5025170},
abstract = {We study the performance of the two-determinant (TD) coupled-cluster (CC) method which, unlike conventional ground-state single-reference (SR) CC methods, can, in principle, provide a naturally spin-adapted treatment of the lowest-lying open-shell singlet (OSS) and triplet electronic states. Various choices for the TD-CC reference orbitals are considered, including those generated by the multi-configurational self-consistent field method. Comparisons are made with the results of high-level SR-CC, equation-of-motion (EOM) CC, and multi-reference EOM calculations performed on a large test set of over 100 molecules with low-lying OSS states. It is shown that in cases where the EOMCC reference function is poorly described, TD-CC can provide a significantly better quantitative description of OSS total energies and OSS-triplet splittings.},
date-modified = {2022-03-23 11:52:11 +0100},
file = {/Users/monino/Zotero/storage/NF5IK6NF/Lutz et al. - 2018 - Reference dependence of the two-determinant couple.pdf}
title = {The `{{Tailored}}' {{CCSD}}({{T}}) Description of the Automerization of Cyclobutadiene},
author = {Lyakh, Dmitry I. and Lotrich, Victor F. and Bartlett, Rodney J.},
year = {2011},
month = jan,
journal = {Chem. Phys. Lett.},
volume = {501},
number = {4},
pages = {166--171},
issn = {0009-2614},
doi = {10.1016/j.cplett.2010.11.058},
abstract = {An alternative route to extend the CCSD(T) approach to multireference problems is presented. The well-known defect of the CCSD(T) model in describing the non-dynamic electron correlation effects is remedied by `tailoring' the underlying coupled-cluster singles and doubles (CCSD) approach and applying the perturbative triples correction to it. The TCCSD(T) approach suggested in the paper has the same computational demands as the CCSD(T) method, though being mostly free from its drawbacks pertinent to multireference (quasidegenerate) situations. To test the approach we calculate the potential energy surface for the automerization of cyclobutadiene where the transition state exhibits a strong multireference character.},
title = {{Second-order state-specific multireference M\o ller Plesset perturbation theory: Application to energy surfaces of diimide, ethylene, butadiene, and cyclobutadiene}},
author = {Mahapatra, Uttam Sinha and Chattopadhyay, Sudip and Chaudhuri, Rajat K.},
year = {2010},
journal = {J. Comput. Chem.},
volume = {32},
number = {2},
pages = {325--337},
issn = {1096-987X},
doi = {10.1002/jcc.21624},
abstract = {The complete active space spin-free state-specific multireference M\o ller-Plesset perturbation theory (SS-MRMPPT) based on the Rayleigh-Schr\"odinger expansion has proved to be very successful in describing electronic states of model and real molecular systems with predictive accuracy. The SS-MRMPPT method (which deals with one state while using a multiconfigurational reference wave function) is designed to avoid intruder effects along with a balanced description of both dynamic and static correlations in a size-extensive manner, which allows us to produce accurate potential energy surfaces (PESs) with a correct shape in bond-breaking processes. The SS-MRMPPT method is size consistent when localized orbitals on each fragment are used. The intruder state(s) almost inevitably interfere when computing the PESs involving the breaking of genuine chemical bonds. In such situations, the traditional effective Hamiltonian formalism often goes down, so that no physically acceptable solution can be obtained. In this work, we continue our analysis of the SS-MRMPPT method for systems and phenomena that cannot be described either with the conventional single-reference approach or effective Hamiltonian-based traditional MR methods. In this article, we investigate whether the encouraging results we have obtained at the SS-MRMPPT level in the study of cis-trans isomerization of diimide (N2H2), ethylene (C2H4), and 1,3-butadiene (C4H6) carry over to the study of chemical reactions. The energy surfaces of the double-bond flipping interconversion of the two equivalent ground and two lowest singlet state structures of cyclobutadiene have also been studied. All results have been discussed and assessed by comparing with other state-of-the-art calculations and corresponding experimental data whenever available. \textcopyright{} 2010 Wiley Periodicals, Inc. J Comput Chem, 2011},
title = {A Noniterative Perturbative Triples Correction for the Spin-Flipping and Spin-Conserving Equation-of-Motion Coupled-Cluster Methods with Single and Double Substitutions},
author = {Manohar, Prashant U. and Krylov, Anna I.},
year = {2008},
month = nov,
journal = {J. Chem. Phys.},
volume = {129},
number = {19},
pages = {194105},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.3013087},
abstract = {A noniterative N 7 N7 triples correction for the equation-of-motion coupled-cluster method with single and double substitutions (CCSD) is presented. The correction is derived by second-order perturbation treatment of the similarity-transformed CCSD Hamiltonian. The spin-conserving variant of the correction is identical to the triples correction of Piecuch and co-workers [Mol. Phys. 104, 2149 (2006)] derived within method-of-moments framework and is not size intensive. The spin-flip variant of the correction is size intensive. The performance of the correction is demonstrated by calculations of electronic excitation energies in methylene, nitrenium ion, cyclobutadiene, ortho-, meta-, and para-benzynes, 1,2,3-tridehydrobenzene, as well as C\textendash C bond breaking in ethane. In all cases except cyclobutadiene, the absolute values of the correction for energy differences were 0.1 eV or less. In cyclobutadiene, the absolute values of the correction were as large as 0.4 eV. In most cases, the correction reduced the errors against the benchmark values by about a factor of 2\textendash 3, the absolute errors being less than 0.04 eV.},
date-modified = {2022-03-23 11:52:20 +0100},
file = {/Users/monino/Zotero/storage/B776SM2U/Manohar et Krylov - 2008 - A noniterative perturbative triples correction for.pdf}
title = {{{$\omega$B97X-V}}: {{A}} 10-{{Parameter}}, Range-Separated Hybrid, Generalized Gradient Approximation Density Functional with Nonlocal Correlation, Designed by a Survival-of-the-Fittest Strategy},
shorttitle = {{{$\omega$B97X-V}}},
author = {Mardirossian, Narbe and {Head-Gordon}, Martin},
year = {2014},
month = may,
journal = {Phys. Chem. Chem. Phys.},
volume = {16},
number = {21},
pages = {9904--9924},
publisher = {{The Royal Society of Chemistry}},
issn = {1463-9084},
doi = {10.1039/C3CP54374A},
abstract = {A 10-parameter, range-separated hybrid (RSH), generalized gradient approximation (GGA) density functional with nonlocal correlation (VV10) is presented. Instead of truncating the B97-type power series inhomogeneity correction factors (ICF) for the exchange, same-spin correlation, and opposite-spin correlation functionals uniformly, all 16 383 combinations of the linear parameters up to fourth order (m = 4) are considered. These functionals are individually fit to a training set and the resulting parameters are validated on a primary test set in order to identify the 3 optimal ICF expansions. Through this procedure, it is discovered that the functional that performs best on the training and primary test sets has 7 linear parameters, with 3 additional nonlinear parameters from range-separation and nonlocal correlation. The resulting density functional, {$\omega$}B97X-V, is further assessed on a secondary test set, the parallel-displaced coronene dimer, as well as several geometry datasets. Furthermore, the basis set dependence and integration grid sensitivity of {$\omega$}B97X-V are analyzed and documented in order to facilitate the use of the functional.},
date-modified = {2022-03-23 11:52:23 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/PBFZUPH8/Mardirossian et Head-Gordon - 2014 - ωB97X-V A 10-parameter, range-separated hybrid, g.pdf;/Users/monino/Zotero/storage/62SX8LRD/c3cp54374a.html}
title = {Coupled-Cluster Techniques for Computational Chemistry: {{The CFOUR}} Program Package},
author = {Matthews, Devin A. and Cheng, Lan and Harding, Michael E. and Lipparini, Filippo and Stopkowicz, Stella and Jagau, Thomas-C. and Szalay, P{\'e}ter G. and Gauss, J{\"u}rgen and Stanton, John F.},
title = {Calculation of Properties with the Coupled-Cluster Method},
author = {Monkhorst, Hendrik J.},
year = {1977},
journal = {Int. J. Quantum Chem.},
volume = {12},
pages = {421--432},
doi = {10.1002/qua.560120850},
abstract = {Abstract The cluster-expansion approach to the correlation problem, pioneered by Cocster, K\"ummel, Cizek and Paldus, is extended to calculation of static and dynamic properties of many-fermion systems. Linear, inhomogeneous equations are obtained for properties of any order. A time-dependent formulation gives frequency-dependent properties, yielding excitation energies, transition probabilities, and (possibly) life times reminiscent of Green's function methods.},
title = {Towards the Solution of the Many-Electron Problem in Real Materials: {{Equation}} of State of the Hydrogen Chain with State-of-the-Art Many-Body Methods},
author = {Motta, Mario and Ceperley, David M and Chan, Garnet Kin-Lic and Gomez, John A and Gull, Emanuel and Guo, Sheng and {Jim{\'e}nez-Hoyos}, Carlos A and Lan, Tran Nguyen and Li, Jia and Ma, Fengjie and others},
title = {Ground-State Properties of the Hydrogen Chain: Insulator-to-Metal Transition, Dimerization, and Magnetic Phases},
author = {Motta, Mario and Genovese, Claudio and Ma, Fengjie and Cui, Zhi-Hao and Sawaya, Randy and Chan, Garnet Kin and Chepiga, Natalia and Helms, Phillip and {Jimenez-Hoyos}, Carlos and Millis, Andrew J and others},
title = {The {{MRCC}} Program System: {{Accurate}} Quantum Chemistry from Water to Proteins},
author = {K{\'a}llay, Mih{\'a}ly and Nagy, P{\'e}ter R. and Mester, D{\'a}vid and Rolik, Zolt{\'a}n and Samu, Gyula and Csontos, J{\'o}zsef and Cs{\'o}ka, J{\'o}zsef and Szab{\'o}, P. Bern{\'a}t and {Gyevi-Nagy}, L{\'a}szl{\'o} and H{\'e}gely, Bence and Ladj{\'a}nszki, Istv{\'a}n and Szegedy, L{\'o}r{\'a}nt and Lad{\'o}czki, Bence and Petrov, Kl{\'a}ra and Farkas, M{\'a}t{\'e} and Mezei, P{\'a}l D. and Ganyecz, {\'A}d{\'a}m},
title = {Slow Convergence of the {{M}}\textendash{{Plesset}} Perturbation Series: The Dissociation Energy of Hydrogen Cyanide and the Electron Affinity of the Cyano Radical},
author = {Nobes, R. H. and Pople, J. A. and Radom, L. and Handy, N. C. and Knowles, P. J.},
title = {Towards a Full {{CCSDT}} Model for Electron Correlation. {{CCSDT-n}} Models},
author = {Noga, Jozef and Bartlett, Rodney J. and Urban, Miroslav},
year = {1987},
journal = {Chem. Phys. Lett.},
volume = {134},
number = {2},
pages = {126--132},
doi = {10.1016/0009-2614(87)87107-5},
abstract = {The first numerical results using two extended coupled cluster models that include triple excitations, CCSDT-2 and CCSDT-3, are reported and compared to full CI for several systems. These methods are shown to be superior to CCSDT-1 when the reference function is poor, such as in bond breaking cases. The errors compared to full CI vary from 0.1 to 1.2 kcalmol.},
title = {Correlation Problems in Atomic and Molecular Systems. {{IV}}. {{Extended}} Coupled-Pair Many-Electron Theory and Its Application to the {{bH}}{$_3$} Molecule},
author = {Paldus, J. and {\v}C{\v C}{\textacutewedge i}z{\v z}ek, J. and Shavitt, I.},
title = {Improving the {{Accuracy}} of {{Hybrid Meta-GGA Density Functionals}} by {{Range Separation}}},
author = {Peverati, Roberto and Truhlar, Donald G.},
year = {2011},
month = nov,
journal = {J. Phys. Chem. Lett.},
volume = {2},
number = {21},
pages = {2810--2817},
publisher = {{American Chemical Society}},
doi = {10.1021/jz201170d},
abstract = {The Minnesota family of exchange\textendash correlation functionals, which consists of meta generalized gradient approximations (meta-GGAs) and global-hybrid meta-GGAs, has been successful for density functional calculations of molecular structure, properties, and thermochemistry, kinetics, noncovalent interactions, and spectroscopy. Here, we generalize the functional form by using range-separated hybrid meta-GGA exchange. We optimize a functional, called M11, with the new form against a broad database of energetic chemical properties and compare its performance to that of several other functionals, including previous Minnesota functionals. We require the percentage of Hartree\textendash Fock exchange to be 100 at large interelectronic distance, and we find an optimum percentage of 42.8 at short range. M11 has good across-the-board performance and the smallest mean unsigned error over the whole test set of 332 data; it has especially good performance for main-group atomization energies, proton affinities, electron affinities, alkyl bond dissociation energies, barrier heights, noncovalent interaction energies, and charge-transfer electronic excitation.},
date-modified = {2022-03-23 11:53:13 +0100},
file = {/Users/monino/Zotero/storage/8VJHHE9A/Peverati et Truhlar - 2011 - Improving the Accuracy of Hybrid Meta-GGA Density .pdf;/Users/monino/Zotero/storage/3XX4Q593/jz201170d.html}
}
@article{Piecuch_2002,
title = {Recent Advances in Electronic Structure Theory: {{Method}} of Moments of Coupled-Cluster Equations and Renormalized Coupled-Cluster Approaches},
author = {Piecuch, Piotr and Kowalski, Karol and Pimienta, Ian S. O. and Mcguire, Michael J.},
title = {Efficient Computer Implementation of the Renormalized Coupled-Cluster Methods: {{The R-CCSD}}[{{T}}], r-Ccsd(t), {{CR-CCSD}}[{{T}}], and {{CR-CCSD}}({{T}}) Approaches},
author = {Piecuch, Piotr and Kucharski, Stanis{\l}aw A. and Kowalski, Karol and Musia{\l}, Monika},
title = {Recent Advances in Electronic Structure Theory: {{Method}} of Moments of Coupled-Cluster Equations and Renormalized Coupled-Cluster Approaches},
author = {Piecuch, Piotr and Kowalski, Karol and Pimienta, Ian S. O. and Mcguire, Michael J.},
title = {Theoretical Models Incorporating Electron Correlation},
author = {Pople, John A. and Binkley, J. Stephen and Seeger, Rolf},
year = {1976},
journal = {Int. J. Quantum Chem.},
volume = {10},
number = {S10},
pages = {1--19},
doi = {10.1002/qua.560100802},
abstract = {Abstract Some methods of describing electron correlation are compared from the point of view of requirements for theoretical chemical models. The perturbation approach originally introduced by M\o ller and Plesset, terminated at finite order, is found to satisfy most of these requirements. It is size consistent, that is, applicable to an ensemble of isolated systems in an additive manner. On the other hand, it does not provide an upper bound for the electronic energy. The independent electron-pair approximation is accurate to second order in a M\o ller-Plesset expansion, but inaccurate in third order. A series of variational methods is discussed which gives upper bounds for the energy, but which lacks size consistency. Finally, calculations on some small molecules using a moderately large Gaussian basis are presented to illustrate these points. Equilibrium geometries, dissociation energies, and energy separations between electronic states of different spin multiplicities are described substantially better by Moller-Plesset theory to second or third order than by Hartree-Fock theory.},
title = {Software for the Frontiers of Quantum Chemistry: {{An}} Overview of Developments in the {{Q-Chem}} 5 Package},
author = {Epifanovsky, Evgeny and Gilbert, Andrew T. B. and Feng, Xintian and Lee, Joonho and Mao, Yuezhi and Mardirossian, Narbe and Pokhilko, Pavel and White, Alec F. and Coons, Marc P. and Dempwolff, Adrian L. and Gan, Zhengting and Hait, Diptarka and Horn, Paul R. and Jacobson, Leif D. and Kaliman, Ilya and Kussmann, J{\"o}rg and Lange, Adrian W. and Lao, Ka Un and Levine, Daniel S. and Liu, Jie and McKenzie, Simon C. and Morrison, Adrian F. and Nanda, Kaushik D. and Plasser, Felix and Rehn, Dirk R. and Vidal, Marta L. and You, Zhi-Qiang and Zhu, Ying and Alam, Bushra and Albrecht, Benjamin J. and Aldossary, Abdulrahman and Alguire, Ethan and Andersen, Josefine H. and Athavale, Vishikh and Barton, Dennis and Begam, Khadiza and Behn, Andrew and Bellonzi, Nicole and Bernard, Yves A. and Berquist, Eric J. and Burton, Hugh G. A. and Carreras, Abel and {Carter-Fenk}, Kevin and Chakraborty, Romit and Chien, Alan D. and Closser, Kristina D. and {Cofer-Shabica}, Vale and Dasgupta, Saswata and {de Wergifosse}, Marc and Deng, Jia and Diedenhofen, Michael and Do, Hainam and Ehlert, Sebastian and Fang, Po-Tung and Fatehi, Shervin and Feng, Qingguo and Friedhoff, Triet and Gayvert, James and Ge, Qinghui and Gidofalvi, Gergely and Goldey, Matthew and Gomes, Joe and {Gonz{\'a}lez-Espinoza}, Cristina E. and Gulania, Sahil and Gunina, Anastasia O. and {Hanson-Heine}, Magnus W. D. and Harbach, Phillip H. P. and Hauser, Andreas and Herbst, Michael F. and Hern{\'a}ndez Vera, Mario and Hodecker, Manuel and Holden, Zachary C. and Houck, Shannon and Huang, Xunkun and Hui, Kerwin and Huynh, Bang C. and Ivanov, Maxim and J{\'a}sz, {\'A}d{\'a}m and Ji, Hyunjun and Jiang, Hanjie and Kaduk, Benjamin and K{\"a}hler, Sven and Khistyaev, Kirill and Kim, Jaehoon and Kis, Gergely and Klunzinger, Phil and {Koczor-Benda}, Zsuzsanna and Koh, Joong Hoon and Kosenkov, Dimitri and Koulias, Laura and Kowalczyk, Tim and Krauter, Caroline M. and Kue, Karl and Kunitsa, Alexander and Kus, Thomas and Ladj{\'a}nszki, Istv{\'a}n and Landau, Arie and Lawler, Keith V. and Lefrancois, Daniel and Lehtola, Susi and Li, Run R. and Li, Yi-Pei and Liang, Jiashu and Liebenthal, Marcus and Lin, Hung-Hsuan and Lin, You-Sheng and Liu, Fenglai and Liu, Kuan-Yu and Loipersberger, Matthias and Luenser, Arne and Manjanath, Aaditya and Manohar, Prashant and Mansoor, Erum and Manzer, Sam F. and Mao, Shan-Ping and Marenich, Aleksandr V. and Markovich, Thomas and Mason, Stephen and Maurer, Simon A. and McLaughlin, Peter F. and Menger, Maximilian F. S. J. and Mewes, Jan-Michael and Mewes, Stefanie A. and Morgante, Pierpaolo and Mullinax, J. Wayne and Oosterbaan, Katherine J. and Paran, Garrette and Paul, Alexander C. and Paul, Suranjan K. and Pavo{\v s}evi{\'c}, Fabijan and Pei, Zheng and Prager, Stefan and Proynov, Emil I. and R{\'a}k, {\'A}d{\'a}m and {Ramos-Cordoba}, Eloy and Rana, Bhaskar and Rask, Alan E. and Rettig, Adam and Richard, Ryan M. and Rob, Fazle and Rossomme, Elliot and Scheele, Tarek and Scheurer, Maximilian and Schneider, Matthias and Sergueev, Nickolai and Sharada, Shaama M. and Skomorowski, Wojciech and Small, David W. and Stein, Christopher J. and Su, Yu-Chuan and Sundstrom, Eric J. and Tao, Zhen and Thirman, Jonathan and Tornai, G{\'a}bor J. and Tsuchimochi, Takashi and Tubman, Norm M. and Veccham, Srimukh Prasad and Vydrov, Oleg and Wenzel, Jan and Witte, Jon and Yamada, Atsushi and Yao, Kun and Yeganeh, Sina and Yost, Shane R. and Zech, Alexander and Zhang, Igor Ying and Zhang, Xing and Zhang, Yu and Zuev, Dmitry and {Aspuru-Guzik}, Al{\'a}n and Bell, Alexis T. and Besley, Nicholas A. and Bravaya, Ksenia B. and Brooks, Bernard R. and Casanova, David and Chai, Jeng-Da and Coriani, Sonia and Cramer, Christopher J. and Cserey, Gy{\"o}rgy and DePrince, A. Eugene and DiStasio, Robert A. and Dreuw, Andreas and Dunietz, Barry D. and Furlani, Thomas R. and Goddard, William A. and {Hammes-Schiffer}, Sharon and {Head-Gordon}, Teresa and Hehre, Warren J. and Hsu, Chao-Ping and Jagau, Thomas-C. and Jung, Yousung and Klamt, Andreas and Kong, Jing and Lambrecht, Daniel
title = {Absence of Superconductivity in the Pure Two-Dimensional {{Hubbard}} Model},
author = {Qin, Mingpu and Chung, Chia-Min and Shi, Hao and Vitali, Ettore and Hubig, Claudius and Schollw{\"o}ck, Ulrich and White, Steven R and Zhang, Shiwei and others},
title = {Photoisomerization of {{Silyl-Substituted Cyclobutadiene Induced}} by {{$\sigma$ \textrightarrow}} {{$\pi$}}* {{Excitation}}: {{A Computational Study}}},
shorttitle = {Photoisomerization of {{Silyl-Substituted Cyclobutadiene Induced}} by {{$\sigma$ \textrightarrow}} {{$\pi$}}* {{Excitation}}},
author = {Qu, Zexing and Yang, Chen and Liu, Chungen},
year = {2015},
month = jan,
journal = {J. Phys. Chem. A},
volume = {119},
number = {3},
pages = {442--451},
publisher = {{American Chemical Society}},
issn = {1089-5639},
doi = {10.1021/jp503220q},
abstract = {Photoinduced chemical processes upon Franck\textendash Condon (FC) excitation in tetrakis(trimethylsilyl)-cyclobutadiene (TMS-CBD) have been investigated through the exploration of potential energy surface crossings among several low-lying excited states using the complete active space self-consistent field (CASSCF) method. Vertical excitation energies are also computed with the equation-of-motion coupled-cluster model with single and double excitations (EOM-CCSD) as well as the multireference M\o ller\textendash Plesset (MRMP) methods. Upon finding an excellent coincidence between the computational results and experimental observations, it is suggested that the Franck\textendash Condon excited state does not correspond to the first {$\pi$}\textendash{$\pi$}* single excitation state (S1, 11B1 state in terms of D2 symmetry), but to the second 1B1 state (S3), which is characterized as a {$\sigma$}\textendash{$\pi$}* single excitation state. Starting from the Franck\textendash Condon region, a series of conical intersections (CIs) are located along one isomerization channel and one dissociation channel. Through the isomerization channel, TMS-CBD is transformed to tetrakis(trimethylsilyl)-tetrahedrane (TMS-THD), and this isomerization process could take place by passing through a ``tetra form'' conical intersection. On the other hand, the dissociation channel yielding two bis(trimethylsilyl)-acetylene (TMS-Ac) molecules through further stretching of the longer C\textendash C bonds might be more competitive than the isomerization channel after excitation into S3 state. This mechanistic picture is in good agreement with recently reported experimental observations.},
date-modified = {2022-03-23 11:53:18 +0100},
file = {/Users/monino/Zotero/storage/9XC7K3P2/Qu et al. - 2015 - Photoisomerization of Silyl-Substituted Cyclobutad.pdf;/Users/monino/Zotero/storage/5NT4FC7W/jp503220q.html}
title = {Further Experiments Pertaining to the Ground State of Cyclobutadiene},
author = {Reeves, P. C. and Henery, J. and Pettit, R.},
year = {1969},
month = oct,
journal = {J. Am. Chem. Soc.},
volume = {91},
number = {21},
pages = {5888--5890},
publisher = {{American Chemical Society}},
issn = {0002-7863},
doi = {10.1021/ja01049a042},
date-modified = {2022-03-23 11:53:22 +0100},
file = {/Users/monino/Zotero/storage/I2PMD3A4/Reeves et al. - 1969 - Further experiments pertaining to the ground state.pdf;/Users/monino/Zotero/storage/3HBEL5FV/ja01049a042.html}
title = {Single-Reference Theories of Molecular Excited States with Single and Double Substitutions},
author = {Rico, Rudolph J. and {Head-Gordon}, Martin},
year = {1993},
journal = {Chem. Phys. Lett.},
volume = {213},
number = {3},
pages = {224--232},
doi = {10.1016/0009-2614(93)85124-7},
abstract = {Several single-reference excited-state methods based on single and double substitutions are considered. Quadratic configuration interaction (QCISD) and coupled-cluster theory (CCSD) are obtained in a time-dependent linear response framework, together with the CISD method. The QCISD and CCSD transition energies are size consistent, and exact for two-electron systems. The relation between the QCISD and CCSD excited-state theories and ground-state gradient expressions is developed and employed. Calculations are reported for singlet and triplet excited states of some small molecules. CCSD and QCISD are qualitatively superior to CISD. Overall, CCSD exhibits noticeably better accuracy than QCISD, and the differences are sometimes much larger than for ground-state problems. A possible explanation is suggested.},
title = {A {{Computational Strategy}} for {{Organic Photochemistry}}},
booktitle = {Reviews in {{Computational Chemistry}}},
author = {Robb, Michael A. and Garavelli, Marco and Olivucci, Massimo and Bernardi, Fernando},
editor = {Lipkowitz, Kenny B. and Boyd, Donald B.},
year = {2007},
pages = {87--146},
publisher = {{John Wiley \& Sons, Inc.}},
address = {{Hoboken, NJ, USA}},
doi = {10.1002/9780470125922.ch2},
date-added = {2022-03-21 21:37:02 +0100},
date-modified = {2022-03-21 21:37:02 +0100},
isbn = {978-0-470-12592-2 978-0-471-36168-8}
}
@incollection{Roos_1995a,
title = {Theoretical Studies of the Electronic Spectra of Organic Molecules},
booktitle = {Quantum Mechanical Electronic Structure Calculations with Chemical Accuracy},
author = {Roos, Bj{\"o}rn O. and F{\"u}lscher, Markus and Malmqvist, Per-{\AA}ke and Merch{\'a}n, Manuela and {Serrano-Andr{\'e}s}, Luis},
year = {1995},
pages = {357--438},
publisher = {{Springer Netherlands}},
address = {{Dordrecht}},
doi = {10.1007/978-94-011-0193-6_8},
abstract = {The complete active space (CAS) SCF method in conjunction with multiconfigurational second-order perturbation theory (CASPT2) has been used to study the electronic spectra of a large number of molecules. The wave functions and the transition properties are computed at the CASSCF level, while dynamic correlation contributions to the excitation energies are obtained through the perturbation treatment. The methods yield energies, which are accurate to at least 0.2 eV, except in a few cases, where the CASSCF reference function does not characterize the electronic state with sufficient accuracy. The applications comprise: the polyenes from ethene to octatetraene (cis- and trans-forms); a number of cyclic pentadienes; norbornadiene; benzene, phenol, phosphabenzene, and the azabenzenes; free base porphin; and the nucleic acid base monomers cytosine, uracil, thymine, and guanine. Finally, the photochemistry of the molecules aminobenzonitrile (ABN) and dimethylaminobenzonitrile (DMABN) has also been studied, in particular the double fluorescence that occurs in DMABN. Taken together these studies comprise large amounts of new spectroscopic data of high accuracy, which either confirm existing assignments of experimental data or lead to new predictions and qualitative as well as quantitative understanding of a large number of electronic spectra. Most studies are restricted to ground state geometries (vertical energies), but in a few cases (octatetraene, ABN, and DMABN) also excited state geometries have been determined, thus yielding 0-0 transition energies and emission spectroscopic data.},
title = {Multiconfigurational Perturbation Theory with Level Shift \textemdash{} the Cr{$_2$} Potential Revisited},
author = {Roos, Bj{\"o}rn O. and Andersson, Kerstin},
year = {1995},
journal = {Chem. Phys. Lett.},
volume = {245},
number = {2},
pages = {215--223},
issn = {0009-2614},
doi = {10.1016/0009-2614(95)01010-7},
abstract = {A level shift technique is suggested for removal of intruder states in multiconfigurational second-order perturbation theory (CASPT2). The first-order wavefunction is first calculated with a level shift parameter large enough to remove the intruder states. The effect of the level shift on the second-order energy is removed by a back correction technique (the LS correction). It is shown that intruder states are removed with little effect on the remaining part of the correlation energy. New potential curves have been computed for the X1{$\Sigma$}g+ and the \'aA\r\r, {$\Delta$}G12 = 535(452) cm-1, D0 = 1.54(1.44) eV. The corresponding values f\'a\'a\'a\'a\AA\AA\AA\AA\AA A\r\r, {$\Delta$}G12 = 667(574) cm-1, Te = 1.79(1.76) eV.},
author = {Roos, Bjorn O. and Andersson, Kerstin and Fulscher, Markus P. and Malmqvist, Per-{\^a}ke and {Serrano-Andr{\'e}s}, Luis and Pierloot, Kristin and Merch{\'a}n, Manuela},
year = {1996},
pages = {219--331},
publisher = {{John Wiley \& Sons, Ltd}},
doi = {10.1002/9780470141526.ch5},
abstract = {This chapter contains sections titled: Introduction Multiconfigurational Perturbation Theory Applications in Spectroscopy Summary},
title = {Benchmarks for Electronically Excited States: {{A}} Comparison of Noniterative and Iterative Triples Corrections in Linear Response Coupled Cluster Methods: {{CCSDR}}(3) versus {{CC3}}},
author = {Sauer, Stephan P. A. and Schreiber, Marko and {Silva-Junior}, Mario R. and Thiel, Walter},
title = {Beyond the Random-Phase Approximation: {{A}} New Approximation Scheme for the Polarization Propagator},
shorttitle = {Beyond the Random-Phase Approximation},
author = {Schirmer, Jochen},
year = {1982},
month = nov,
journal = {Phys. Rev. A},
volume = {26},
number = {5},
pages = {2395--2416},
publisher = {{American Physical Society}},
doi = {10.1103/PhysRevA.26.2395},
abstract = {Within the framework of the many-body Green's-function method we present a new approach to the polarization propagator for finite Fermi systems. This approach makes explicit use of the diagrammatic perturbation expansion for the polarization propagator, and reformulates the exact summation in terms of a simple algebraic scheme, referred to as the algebraic diagrammatic construction (ADC). The ADC defines in a natural way a set of approximation schemes (nth-order ADC schemes) which represent infinite partial summations exact up to nth order of perturbation theory. In contrast to the random-phase-approximation (RPA)-like schemes, the corresponding mathematical procedures are essentially Hermitian eigenvalue problems in limited configuration spaces of unperturbed excited configurations. Explicit equations for the first- and second-order ADC schemes are derived. These schemes are thoroughly discussed and compared with the Tamm-Dancoff approximation and RPA schemes.},
date-modified = {2022-03-23 11:53:30 +0100},
file = {/Users/monino/Zotero/storage/E6ICVKJY/Schirmer - 1982 - Beyond the random-phase approximation A new appro.pdf;/Users/monino/Zotero/storage/VTTD3CQZ/PhysRevA.26.html}
title = {Quantum Mechanical Tunneling in the Automerization of Cyclobutadiene},
author = {Schoonmaker, R. and Lancaster, T. and Clark, S. J.},
year = {2018},
month = mar,
journal = {J. Chem. Phys.},
volume = {148},
number = {10},
pages = {104109},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.5019254},
abstract = {Cyclobutadiene has a four-membered carbon ring with two double bonds, but this highly strained molecular configuration is almost square and, via a coordinated motion, the nuclei quantum mechanically tunnels through the high-energy square state to a configuration equivalent to the initial configuration under a 90\textdegree{} rotation. This results in a square ground state, comprising a superposition of two molecular configurations, that is driven by quantum tunneling. Using a quantum mechanical model, and an effective nuclear potential from density functional theory, we calculate the vibrational energy spectrum and the accompanying wavefunctions. We use the wavefunctions to identify the motions of the molecule and detail how different motions can enhance or suppress the tunneling rate. This is relevant for kinematics of tunneling-driven reactions, and we discuss these implications. We are also able to provide a qualitative account of how the molecule will respond to an external perturbation and how this may enhance or suppress infra-red-active vibrational transitions.},
date-modified = {2022-03-23 11:53:34 +0100},
file = {/Users/monino/Zotero/storage/XWW4NWJN/Schoonmaker et al. - 2018 - Quantum mechanical tunneling in the automerization.pdf}
title = {A New Implementation of the Full {{CCSDT}} Model for Molecular Electronic Structure},
author = {Scuseria, Gustavo E. and Schaefer, Henry F.},
year = {1988},
journal = {Chem. Phys. Lett.},
volume = {152},
number = {4},
pages = {382--386},
issn = {0009-2614},
doi = {10.1016/0009-2614(88)80110-6},
abstract = {A new implementation of the coupled cluster method including all single, double and triple excitations (designated CCSDT) has been developed and carefully tested. Applications to the molecular structures and harmonic vibrational frequencies of HF, OH-, N2 and CO are reported. CCSDT results are in close agreement with those obtained from the configuration interaction method including all single, double, triple and quadruple excitations (CISDTQ).},
title = {Communication: {{Orbital}} Instabilities and Triplet States from Time-Dependent Density Functional Theory and Long-Range Corrected Functionals},
author = {Sears, John S. and Koerzdoerfer, Thomas and Zhang, Cai-Rong and Br{\'e}das, Jean-Luc},
title = {A Linear Response, Coupled-Cluster Theory for Excitation Energy},
author = {Sekino, Hideo and Bartlett, Rodney J.},
year = {1984},
journal = {Int. J. Quantum Chem.},
volume = {26},
number = {S18},
pages = {255--265},
doi = {10.1002/qua.560260826},
abstract = {Abstract Expressions for static and dynamic properties in coupled-cluster (CC) theory are derived. In the static case, using diagrammatic techniques, it is shown how consideration of orbital relaxation effects in the theory introduces higher-order correlation effects. For the dynamic case, excitation energy expressions are obtained without consideration of orbital relaxation effects and shown to be equivalent to an equation of motion (EOM) approach subject to a coupled-cluster ground-state wave function and an excitation operator consisting of single and double excitations. Illustrative applications for excited states of ethylene are reported.},
title = {Advances in Molecular Quantum Chemistry Contained in the {{Q-Chem}} 4 Program Package},
author = {Shao, Yihan and Gan, Zhengting and Epifanovsky, Evgeny and Gilbert, Andrew T.B. and Wormit, Michael and Kussmann, Joerg and Lange, Adrian W. and Behn, Andrew and Deng, Jia and Feng, Xintian and Ghosh, Debashree and Goldey, Matthew and Horn, Paul R. and Jacobson, Leif D. and Kaliman, Ilya and Khaliullin, Rustam Z. and Ku{\'s}, Tomasz and Landau, Arie and Liu, Jie and Proynov, Emil I. and Rhee, Young Min and Richard, Ryan M. and Rohrdanz, Mary A. and Steele, Ryan P. and Sundstrom, Eric J. and Woodcock, H. Lee and Zimmerman, Paul M. and Zuev, Dmitry and Albrecht, Ben and Alguire, Ethan and Austin, Brian and Beran, Gregory J. O. and Bernard, Yves A. and Berquist, Eric and Brandhorst, Kai and Bravaya, Ksenia B. and Brown, Shawn T. and Casanova, David and Chang, Chun-Min and Chen, Yunqing and Chien, Siu Hung and Closser, Kristina D. and Crittenden, Deborah L. and Diedenhofen, Michael and DiStasio, Robert A. and Do, Hainam and Dutoi, Anthony D. and Edgar, Richard G. and Fatehi, Shervin and {Fusti-Molnar}, Laszlo and Ghysels, An and {Golubeva-Zadorozhnaya}, Anna and Gomes, Joseph and {Hanson-Heine}, Magnus W.D. and Harbach, Philipp H.P. and Hauser, Andreas W. and Hohenstein, Edward G. and Holden, Zachary C. and Jagau, Thomas-C. and Ji, Hyunjun and Kaduk, Benjamin and Khistyaev, Kirill and Kim, Jaehoon and Kim, Jihan and King, Rollin A. and Klunzinger, Phil and Kosenkov, Dmytro and Kowalczyk, Tim and Krauter, Caroline M. and Lao, Ka Un and Laurent, Ad{\`e}le D. and Lawler, Keith V. and Levchenko, Sergey V. and Lin, Ching Yeh and Liu, Fenglai and Livshits, Ester and Lochan, Rohini C. and Luenser, Arne and Manohar, Prashant and Manzer, Samuel F. and Mao, Shan-Ping and Mardirossian, Narbe and Marenich, Aleksandr V. and Maurer, Simon A. and Mayhall, Nicholas J. and Neuscamman, Eric and Oana, C. Melania and {Olivares-Amaya}, Roberto and O'Neill, Darragh P. and Parkhill, John A. and Perrine, Trilisa M. and Peverati, Roberto and Prociuk, Alexander and Rehn, Dirk R. and Rosta, Edina and Russ, Nicholas J. and Sharada, Shaama M. and Sharma, Sandeep and Small, David W. and Sodt, Alexander and Stein, Tamar and St{\"u}ck, David and Su, Yu-Chuan and Thom, Alex J.W. and Tsuchimochi, Takashi and Vanovschi, Vitalii and Vogt, Leslie and Vydrov, Oleg and Wang, Tao and Watson, Mark A. and Wenzel, Jan and White, Alec and Williams, Christopher F. and Yang, Jun and Yeganeh, Sina and Yost, Shane R. and You, Zhi-Qiang and Zhang, Igor Ying and Zhang, Xing and Zhao, Yan and Brooks, Bernard R. and Chan, Garnet K.L. and Chipman, Daniel M. and Cramer, Christopher J. and Goddard, William A. and Gordon, Mark S. and Hehre, Warren J. and Klamt, Andreas and Schaefer, Henry F. and Schmidt, Michael W. and Sherrill, C. David and Truhlar, Donald G. and Warshel, Arieh and Xu, Xin and {Aspuru-Guzik}, Al{\'a}n and Baer, Roi and Bell, Alexis T. and Besley, Nicholas A. and Chai, Jeng-Da and Dreuw, Andreas and Dunietz, Barry D. and Furlani, Thomas R. and Gwaltney, Steven R. and Hsu, Chao-Ping and Jung, Yousung and Kong, Jing and Lambrecht, Daniel S. and Liang, WanZhen and Ochsenfeld, Christian and Rassolov, Vitaly A. and Slipchenko, Lyudmila V. and Subotnik, Joseph E. and Van Voorhis, Troy and Herbert, John M. and Krylov, Anna I. and Gill, Peter M.W. and {Head-Gordon}, Martin},
year = {2015},
month = jan,
journal = {Mol. Phys.},
volume = {113},
number = {2},
pages = {184--215},
publisher = {{Taylor \& Francis}},
issn = {0026-8976},
doi = {10.1080/00268976.2014.952696},
abstract = {A summary of the technical advances that are incorporated in the fourth major release of the Q-Chem quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order M\o ller\textendash Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr2 dimer, exploring zeolite-catalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.},
date-modified = {2022-03-23 11:53:38 +0100},
file = {/Users/monino/Zotero/storage/XPUBH7XK/Shao et al. - 2015 - Advances in molecular quantum chemistry contained .pdf;/Users/monino/Zotero/storage/EEKMS8FG/00268976.2014.html}
title = {Combining Active-Space Coupled-Cluster Methods with Moment Energy Corrections via the {{CC}}({{P}};{{Q}}) Methodology, with Benchmark Calculations for Biradical Transition States},
author = {Shen, Jun and Piecuch, Piotr},
year = {2012},
month = apr,
journal = {J. Chem. Phys.},
volume = {136},
number = {14},
pages = {144104},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.3700802},
abstract = {We have recently suggested the CC(P;Q) methodology that can correct energies obtained in the active-space coupled-cluster (CC) or equation-of-motion (EOM) CC calculations, which recover much of the nondynamical and some dynamical electron correlation effects, for the higher-order, mostly dynamical, correlations missing in the active-space CC/EOMCC considerations. It is shown that one can greatly improve the description of biradical transition states, both in terms of the resulting energy barriers and total energies, by combining the CC approach with singles, doubles, and active-space triples, termed CCSDt, with the CC(P;Q)-style correction due to missing triple excitations defining the CC(t;3) approximation.},
title = {Doubly {{Excited Character}} or {{Static Correlation}} of the {{Reference State}} in the {{Controversial}} 2 {$^1$} {{A}} {\textsubscript{g}} {{State}} of {\emph{Trans}} -{{Butadiene}}?},
title = {Benchmarks for Electronically Excited States: {{Time-dependent}} Density Functional Theory and Density Functional Theory Based Multireference Configuration Interaction},
author = {{Silva-Junior}, M. R. and Schreiber, M. and Sauer, S. P. A. and Thiel, W.},
author = {Sneskov, Kristian and Christiansen, Ove},
year = {2012},
journal = {WIREs Comput. Mol. Sci.},
volume = {2},
pages = {566--584},
doi = {10.1002/wcms.99},
abstract = {Abstract We review coupled cluster (CC) theory for electronically excited states. We outline the basics of a CC response theory framework that allows the transfer of the attractive accuracy and convergence properties associated with CC methods over to the calculation of electronic excitation energies and properties. Key factors affecting the accuracy of CC excitation energy calculations are discussed as are some of the key CC models in this field. To aid both the practitioner as well as the developer of CC excited state methods, we also briefly discuss the key computational steps in a working CC response implementation. Approaches aimed at extending the application range of CC excited state methods either in terms of molecular size and phenomena or in terms of environment (solution and proteins) are also discussed. 2011 John Wiley \& Sons, Ltd. This article is categorized under: Electronic Structure Theory \textquestiondown{} Ab Initio Electronic Structure Methods},
title = {The Equation of Motion Coupled-cluster Method. {{A}} Systematic Biorthogonal Approach to Molecular Excitation Energies, Transition Probabilities, and Excited State Properties},
author = {Stanton, John F. and Bartlett, Rodney J.},
title = {Systematic Design of Active Spaces for Multi-Reference Calculations of {{Singlet}}\textendash{{Triplet}} Gaps of Organic Diradicals, with Benchmarks against Doubly Electron-Attached Coupled-Cluster Data},
author = {Stoneburner, Samuel J. and Shen, Jun and Ajala, Adeayo O. and Piecuch, Piotr and Truhlar, Donald G. and Gagliardi, Laura},
year = {2017},
month = oct,
journal = {J. Chem. Phys.},
volume = {147},
number = {16},
pages = {164120},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.4998256},
abstract = {Singlet-triplet gaps in diradical organic {$\pi$}-systems are of interest in many applications. In this study, we calculate them in a series of molecules, including cyclobutadiene and its derivatives and cyclopentadienyl cation, by using correlated participating orbitals within the complete active space (CAS) and restricted active space (RAS) self-consistent field frameworks, followed by second-order perturbation theory (CASPT2 and RASPT2). These calculations are evaluated by comparison with the results of doubly electron-attached (DEA) equation-of-motion (EOM) coupled-cluster (CC) calculations with up to 4-particle\textendash 2-hole (4p-2h) excitations. We find active spaces that can accurately reproduce the DEA-EOMCC(4p-2h) data while being small enough to be applicable to larger organic diradicals.},
date-modified = {2022-03-23 11:53:44 +0100},
file = {/Users/monino/Zotero/storage/59VEQ8FL/Stoneburner et al. - 2017 - Systematic design of active spaces for multi-refer.pdf}
title = {A General Second Order Complete Active Space Self-Consistent-Field Solver for Large-Scale Systems},
author = {Sun, Qiming and Yang, Jun and Chan, Garnet Kin-Lic},
year = {2017},
journal = {Chem. Phys. Lett.},
volume = {683},
pages = {291--299},
doi = {10.1016/j.cplett.2017.03.004},
abstract = {We present a new second order complete active space self-consistent field implementation to converge wavefunctions for both large active spaces and large atomic orbital (AO) bases. Our algorithm decouples the active space wavefunction solver from the orbital optimization in the microiterations, and thus may be easily combined with various modern active space solvers. We also introduce efficient approximate orbital gradient and Hessian updates, and step size determination. We demonstrate its capabilities by calculating the low-lying states of the Fe(II)-porphine complex with modest resources using a density matrix renormalization group solver in a CAS(22,27) active space and a 3000 AO basis.},
title = {Polarization Propagator Study of Electronic Excitation in Key Heterocyclic Molecules {{I}}. {{Pyrrole}}},
author = {Trofimov, A. B. and Schirmer, J.},
year = {1997},
month = jan,
journal = {Chem. Phys.},
volume = {214},
number = {2},
pages = {153--170},
issn = {0301-0104},
doi = {10.1016/S0301-0104(96)00303-5},
abstract = {The electronic excitation spectrum of pyrrole is studied using a polarization propagator method referred to as the second-order algebraic-diagrammatic construction (ADC(2)), along with a simple model for vibrational excitation accounting for all totally symmetric modes. The method describes the optical absorption profile of pyrrole with an expected accuracy of 0.2 \textendash{} 0.4 eV for the vertical excitation energies. The vibrational analysis provides for detailed additional spectroscopic information. In the singlet spectrum, besides the ns, np and nd (n = 3,4) Rydberg excitations, three {$\pi$}-{$\pi$} valence transitions, V'(1A1), V(1B2) and V(1A1) can clearly be distinguished. No evidence is found for Rydberg-valence interaction near the equilibrium geometry. Substantial vibrational widths and distinct vibrational excitation patterns are predicted for the Rydberg series converging to the first and second ionization thresholds. Some new assignments of major spectral features are proposed. The long-wave absorption maximum in the 5.6 \textendash{} 6.6. eV region is explained exclusively by the presence of Rydberg transitions, while the most intense absorption in the short-wave band system (7.0 \textendash{} 8.3 ev) predominantly originates from the V(1B2) and V(1A1) valence transitions.},
date-modified = {2022-03-23 11:53:49 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/32BM4TYM/Trofimov et Schirmer - 1997 - Polarization propagator study of electronic excita.pdf;/Users/monino/Zotero/storage/YCGJHMZ3/S0301010496003035.html}
title = {Electron Excitation Energies Using a Consistent Third-Order Propagator Approach: {{Comparison}} with Full Configuration Interaction and Coupled Cluster Results},
shorttitle = {Electron Excitation Energies Using a Consistent Third-Order Propagator Approach},
author = {Trofimov, A. B. and Stelter, G. and Schirmer, J.},
year = {2002},
month = oct,
journal = {J. Chem. Phys.},
volume = {117},
number = {14},
pages = {6402--6410},
publisher = {{American Institute of Physics}},
issn = {0021-9606},
doi = {10.1063/1.1504708},
date-modified = {2022-03-23 11:53:51 +0100},
file = {/Users/monino/Zotero/storage/836QTTRI/Trofimov et al. - 2002 - Electron excitation energies using a consistent th.pdf}
title = {The Transition State of the Automerization Reaction of Cyclobutadiene: {{A}} Theoretical Approach Using the {{Restricted Active Space Self Consistent Field}} Method},
shorttitle = {The Transition State of the Automerization Reaction of Cyclobutadiene},
author = {Varras, Panayiotis C. and Gritzapis, Panagiotis S.},
year = {2018},
month = nov,
journal = {Chem. Phys. Lett.},
volume = {711},
pages = {166--172},
issn = {0009-2614},
doi = {10.1016/j.cplett.2018.09.028},
abstract = {The application of the Restricted Active Space Self Consistent Field (RASSCF) quantum chemical method using an extended active space and including {$\sigma$}-{$\sigma$}, {$\pi$}-{$\sigma$} and {$\pi$}-{$\pi$} dynamical electron correlation shows that the transition state structure for the automerization reaction of cyclobutadiene is an isosceles trapezium. This transition state is obtained without any symmetry constraints. The calculated energy barrier height involving the zero point vibrational energy corrections is 9.62\,kcal{$\bullet$}mol-1 (0.417\,eV), with the corresponding rate constant being equal to 0.18\,\texttimes\,109\,s-1 (or 7.1\,\texttimes\,1010\,s-1 in case of using the vibrational energy splitting tunneling method).},
title = {{{QUESTDB}}: {{A}} Database of Highly Accurate Excitation Energies for the Electronic Structure Community},
author = {V{\'e}ril, Micka{\"e}l and Scemama, Anthony and Caffarel, Michel and Lipparini, Filippo and {Boggio-Pasqua}, Martial and Jacquemin, Denis and Loos, Pierre-Fran{\c c}ois},
journal = {WIREs Comput. Mol. Sci.},
volume = {n/a},
number = {n/a},
pages = {e1517},
doi = {10.1002/wcms.1517},
abstract = {Abstract We describe our efforts of the past few years to create a large set of more than 500 highly accurate vertical excitation energies of various natures ({$\pi$} \textrightarrow{} {$\pi$}*, n \textrightarrow{} {$\pi$}*, double excitation, Rydberg, singlet, doublet, triplet, etc.) in small- and medium-sized molecules. These values have been obtained using an incremental strategy which consists in combining high-order coupled cluster and selected configuration interaction calculations using increasingly large diffuse basis sets in order to reach high accuracy. One of the key aspects of the so-called QUEST database of vertical excitations is that it does not rely on any experimental values, avoiding potential biases inherently linked to experiments and facilitating theoretical cross comparisons. Following this composite protocol, we have been able to produce theoretical best estimates (TBEs) with the aug-cc-pVTZ basis set for each of these transitions, as well as basis set corrected TBEs (i.e., near the complete basis set limit) for some of them. The TBEs/aug-cc-pVTZ have been employed to benchmark a large number of (lower-order) wave function methods such as CIS(D), ADC(2), CC2, STEOM-CCSD, CCSD, CCSDR(3), CCSDT-3, ADC(3), CC3, NEVPT2, and so on (including spin-scaled variants). In order to gather the huge amount of data produced during the QUEST project, we have created a website (https://lcpq.github.io/QUESTDB\_website) where one can easily test and compare the accuracy of a given method with respect to various variables such as the molecule size or its family, the nature of the excited states, the type of basis set, and so on. We hope that the present review will provide a useful summary of our effort so far and foster new developments around excited-state methods. This article is categorized under: Electronic Structure Theory \textquestiondown{} Ab Initio Electronic Structure Methods},
title = {{{FCIQMC-Tailored Distinguishable Cluster Approach}}},
author = {Vitale, Eugenio and Alavi, Ali and Kats, Daniel},
year = {2020},
month = sep,
journal = {J. Chem. Theory Comput.},
volume = {16},
number = {9},
pages = {5621--5634},
publisher = {{American Chemical Society}},
issn = {1549-9618},
doi = {10.1021/acs.jctc.0c00470},
abstract = {The tailored approach is applied to the distinguishable cluster method together with a stochastic FCI solver (FCIQMC). It is demonstrated that the new method is more accurate than the corresponding tailored coupled cluster and the pure distinguishable cluster methods. An F12 correction for tailored methods and FCIQMC is introduced, which drastically improves the basis set convergence. A new black-box approach to define the active space using the natural orbitals from the distinguishable cluster is evaluated and found to be a convenient alternative to the usual CASSCF approach.},
title = {Long-{{Range-Corrected Hybrids Based}} on a {{New Model Exchange Hole}}},
author = {Weintraub, Elon and Henderson, Thomas M. and Scuseria, Gustavo E.},
year = {2009},
month = apr,
journal = {J. Chem. Theory Comput.},
volume = {5},
number = {4},
pages = {754--762},
publisher = {{American Chemical Society}},
issn = {1549-9618},
doi = {10.1021/ct800530u},
abstract = {By admixing a fraction of exact Hartree-Fock-type exchange with conventional semilocal functionals, global hybrids greatly improve the accuracy of Kohn-Sham density functional theory. However, because global hybrids exhibit incorrect asymptotic decay of the exchange-correlation potential, they can have large errors for diverse quantities such as reaction barrier heights, nonlinear optical properties, and Rydberg and charge-transfer excitation energies. These errors can be removed by using a long-range-corrected hybrid, which uses exact exchange in the long range. Evaluating the long-range-corrected exchange energy requires a model for the semilocal exchange hole, and such models are scarce. Recently, two of us introduced one such model (J. Chem. Phys. 2008, 128, 194105). This model obeys several exact constraints and was designed specifically for use in long-range-corrected hybrids. Here, we give sample results for three long-range-corrected hybrids based upon our exchange hole model and show how the model can easily be applied to any generalized gradient approximation (GGA) for the exchange energy to create a long-range-corrected GGA.},
date-modified = {2022-03-23 11:54:00 +0100},
file = {/Users/monino/Zotero/storage/GZ242R45/Weintraub et al. - 2009 - Long-Range-Corrected Hybrids Based on a New Model .pdf;/Users/monino/Zotero/storage/QJFMGPF3/ct800530u.html}
title = {A Quadratically Convergent Multiconfiguration\textendash Self-consistent Field Method with Simultaneous Optimization of Orbitals and {{CI}} Coefficients},
author = {Werner, Hans-Joachim and Meyer, Wilfried},
title = {Molpro: {{A}} General-Purpose Quantum Chemistry Program Package},
shorttitle = {Molpro},
author = {Werner, Hans-Joachim and Knowles, Peter J. and Knizia, Gerald and Manby, Frederick R. and Sch{\"u}tz, Martin},
year = {2012},
journal = {WIREs Comput. Mol. Sci.},
volume = {2},
number = {2},
pages = {242--253},
issn = {1759-0884},
doi = {10.1002/wcms.82},
abstract = {Molpro (available at http://www.molpro.net) is a general-purpose quantum chemical program. The original focus was on high-accuracy wave function calculations for small molecules, but using local approximations combined with explicit correlation treatments, highly accurate coupled-cluster calculations are now possible for molecules with up to approximately 100 atoms. Recently, multireference correlation treatments were also made applicable to larger molecules. Furthermore, an efficient implementation of density functional theory is available. \textcopyright{} 2011 John Wiley \& Sons, Ltd. This article is categorized under: Software {$>$} Quantum Chemistry},
date-modified = {2022-03-23 11:54:03 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/EGXFYSIC/Werner et al. - 2012 - Molpro a general-purpose quantum chemistry progra.pdf;/Users/monino/Zotero/storage/UHRUSMN8/wcms.html}
title = {The {{Molpro}} Quantum Chemistry Package},
author = {Werner, Hans-Joachim and Knowles, Peter J. and Manby, Frederick R. and Black, Joshua A. and Doll, Klaus and He{\ss}elmann, Andreas and Kats, Daniel and K{\"o}hn, Andreas and Korona, Tatiana and Kreplin, David A. and Ma, Qianli and Miller, Thomas F. and Mitrushchenkov, Alexander and Peterson, Kirk A. and Polyak, Iakov and Rauhut, Guntram and Sibaev, Marat},
title = {Limits on the Activation Parameters for Automerization of {{Cyclobutadiene-1}},2-{{D2}}},
author = {Whitman, David W. and Carpenter, Barry K.},
year = {1982},
month = nov,
journal = {J. Am. Chem. Soc.},
volume = {104},
number = {23},
pages = {6473--6474},
publisher = {{American Chemical Society}},
issn = {0002-7863},
doi = {10.1021/ja00387a065},
date-modified = {2022-03-23 11:54:06 +0100},
file = {/Users/monino/Zotero/storage/VIBC7IN3/Whitman et Carpenter - 1982 - Limits on the activation parameters for automeriza.pdf;/Users/monino/Zotero/storage/G5GLPK22/ja00387a065.html}
title = {Configuration Interaction Studies of Ground and Excited States of Polyatomic Molecules. {{I}}. {{The CI}} Formulation and Studies of Formaldehyde},
title = {Direct Comparison of Many-Body Methods for Realistic Electronic {{Hamiltonians}}},
author = {Williams, Kiel T and Yao, Yuan and Li, Jia and Chen, Li and Shi, Hao and Motta, Mario and Niu, Chunyao and Ray, Ushnish and Guo, Sheng and Anderson, Robert J and others},
title = {Multireference {{Second Order Perturbation Theory}} with a {{Simplified Treatment}} of {{Dynamical Correlation}}},
author = {Xu, Enhua and Zhao, Dongbo and Li, Shuhua},
year = {2015},
month = oct,
journal = {J. Chem. Theory Comput.},
volume = {11},
number = {10},
pages = {4634--4643},
publisher = {{American Chemical Society}},
issn = {1549-9618},
doi = {10.1021/acs.jctc.5b00495},
abstract = {A multireference second order perturbation theory based on a complete active space configuration interaction (CASCI) function or density matrix renormalized group (DMRG) function has been proposed. This method may be considered as an approximation to the CAS/A approach with the same reference, in which the dynamical correlation is simplified with blocked correlated second order perturbation theory based on the generalized valence bond (GVB) reference (GVB-BCPT2). This method, denoted as CASCI-BCPT2/GVB or DMRG-BCPT2/GVB, is size consistent and has a similar computational cost as the conventional second order perturbation theory (MP2). We have applied it to investigate a number of problems of chemical interest. These problems include bond-breaking potential energy surfaces in four molecules, the spectroscopic constants of six diatomic molecules, the reaction barrier for the automerization of cyclobutadiene, and the energy difference between the monocyclic and bicyclic forms of 2,6-pyridyne. Our test applications demonstrate that CASCI-BCPT2/GVB can provide comparable results with CASPT2 (second order perturbation theory based on the complete active space self-consistent-field wave function) for systems under study. Furthermore, the DMRG-BCPT2/GVB method is applicable to treat strongly correlated systems with large active spaces, which are beyond the capability of CASPT2.},
date-modified = {2022-03-23 11:54:09 +0100},
file = {/Users/monino/Zotero/storage/DJNQ7VLR/Xu et al. - 2015 - Multireference Second Order Perturbation Theory wi.pdf;/Users/monino/Zotero/storage/QBDFQAIR/acs.jctc.html}
title = {Towards Near-Exact Solutions of Molecular Electronic Structure: {{Full}} Coupled-Cluster Reduction with a Second-Order Perturbative Correction},
author = {Xu, Enhua and Uejima, Motoyuki and {Ten-no}, Seiichiro L.},
title = {A New Hybrid {{Exchange}}\textendash{{Correlation}} Functional Using the {{Coulomb-attenuating}} Method ({{CAM-B3LYP}})},
author = {Yanai, Takeshi and Tew, David P and Handy, Nicholas C},
year = {2004},
month = jul,
journal = {Chem. Phys. Lett.},
volume = {393},
number = {1},
pages = {51--57},
issn = {0009-2614},
doi = {10.1016/j.cplett.2004.06.011},
abstract = {A new hybrid exchange\textendash correlation functional named CAM-B3LYP is proposed. It combines the hybrid qualities of B3LYP and the long-range correction presented by Tawada et al. [J. Chem. Phys., in press]. We demonstrate that CAM-B3LYP yields atomization energies of similar quality to those from B3LYP, while also performing well for charge transfer excitations in a dipeptide model, which B3LYP underestimates enormously. The CAM-B3LYP functional comprises of 0.19 Hartree\textendash Fock (HF) plus 0.81 Becke 1988 (B88) exchange interaction at short-range, and 0.65 HF plus 0.35 B88 at long-range. The intermediate region is smoothly described through the standard error function with parameter 0.33.},
title = {Analytic Derivative Couplings in Time-Dependent Density Functional Theory: {{Quadratic}} Response Theory versus Pseudo-Wavefunction Approach},
shorttitle = {Analytic Derivative Couplings in Time-Dependent Density Functional Theory},
author = {Zhang, Xing and Herbert, John M.},
year = {2015},
month = feb,
journal = {J. Chem. Phys.},
volume = {142},
number = {6},
pages = {064109},
issn = {0021-9606, 1089-7690},
doi = {10.1063/1.4907376},
date-added = {2022-03-23 11:49:35 +0100},
date-modified = {2022-03-23 11:49:35 +0100},
langid = {english}
}
@article{Zhang_2019,
title = {Improving the {{Efficiency}} of the {{Multireference Driven Similarity Renormalization Group}} via {{Sequential Transformation}}, {{Density Fitting}}, and the {{Noninteracting Virtual Orbital Approximation}}},
author = {Zhang, Tianyuan and Li, Chenyang and Evangelista, Francesco A.},
title = {The {{M06}} Suite of Density Functionals for Main Group Thermochemistry, Thermochemical Kinetics, Noncovalent Interactions, Excited States, and Transition Elements: {{Two}} New Functionals and Systematic Testing of Four {{M06-class}} Functionals and 12 Other Functionals},
shorttitle = {The {{M06}} Suite of Density Functionals for Main Group Thermochemistry, Thermochemical Kinetics, Noncovalent Interactions, Excited States, and Transition Elements},
author = {Zhao, Yan and Truhlar, Donald G.},
year = {2008},
month = may,
journal = {Theor Chem Acc.},
volume = {120},
number = {1},
pages = {215--241},
issn = {1432-2234},
doi = {10.1007/s00214-007-0310-x},
abstract = {We present two new hybrid meta exchange- correlation functionals, called M06 and M06-2X. The M06 functional is parametrized including both transition metals and nonmetals, whereas the M06-2X functional is a high-nonlocality functional with double the amount of nonlocal exchange (2X), and it is parametrized only for nonmetals.The functionals, along with the previously published M06-L local functional and the M06-HF full-Hartree\textendash Fock functionals, constitute the M06 suite of complementary functionals. We assess these four functionals by comparing their performance to that of 12 other functionals and Hartree\textendash Fock theory for 403 energetic data in 29 diverse databases, including ten databases for thermochemistry, four databases for kinetics, eight databases for noncovalent interactions, three databases for transition metal bonding, one database for metal atom excitation energies, and three databases for molecular excitation energies. We also illustrate the performance of these 17 methods for three databases containing 40 bond lengths and for databases containing 38 vibrational frequencies and 15 vibrational zero point energies. We recommend the M06-2X functional for applications involving main-group thermochemistry, kinetics, noncovalent interactions, and electronic excitation energies to valence and Rydberg states. We recommend the M06 functional for application in organometallic and inorganometallic chemistry and for noncovalent interactions.},
date-modified = {2022-03-23 11:54:16 +0100},
langid = {english},
file = {/Users/monino/Zotero/storage/DST4SA5P/Zhao et Truhlar - 2008 - The M06 suite of density functionals for main grou.pdf}
title = {Stripe Order in the Underdoped Region of the Two-Dimensional {{Hubbard}} Model},
author = {Zheng, Bo-Xiao and Chung, Chia-Min and Corboz, Philippe and Ehlers, Georg and Qin, Ming-Pu and Noack, Reinhard M and Shi, Hao and White, Steven R and Zhang, Shiwei and Chan, Garnet Kin-Lic},
year = {2017},
journal = {Science},
volume = {358},
number = {6367},
pages = {1155--1160},
publisher = {{American Association for the Advancement of Science}},
author = {Zobel, J. Patrick and Nogueira, Juan J. and Gonzalez, Leticia},
year = {2017},
journal = {Chem. Sci.},
volume = {8},
number = {2},
pages = {1482--1499},
publisher = {{The Royal Society of Chemistry}},
doi = {10.1039/C6SC03759C},
abstract = {Multi-configurational second order perturbation theory (CASPT2) has become a very popular method for describing excited-state properties since its development in 1990. To account for systematic errors found in the calculation of dissociation energies, an empirical correction applied to the zeroth-order Hamiltonian, called the IPEA shift, was introduced in 2004. The errors were attributed to an unbalanced description of open-shell versus closed-shell electronic states and is believed to also lead to an underestimation of excitation energies. Here we show that the use of the IPEA shift is not justified and the IPEA should not be used to calculate excited states, at least for organic chromophores. This conclusion is the result of three extensive analyses. Firstly, we survey the literature for excitation energies of organic molecules that have been calculated with the unmodified CASPT2 method. We find that the excitation energies of 356 reference values are negligibly underestimated by 0.02 eV. This value is an order of magnitude smaller than the expected error based on the calculation of dissociation energies. Secondly, we perform benchmark full configuration interaction calculations on 137 states of 13 di- and triatomic molecules and compare the results with CASPT2. Also in this case, the excited states are underestimated by only 0.05 eV. Finally, we perform CASPT2 calculations with different IPEA shift values on 309 excited states of 28 organic small and medium-sized organic chromophores. We demonstrate that the size of the IPEA correction scales with the amount of dynamical correlation energy (and thus with the size of the system), and gets immoderate already for the molecules considered here, leading to an overestimation of the excitation energies. It is also found that the IPEA correction strongly depends on the size of the basis set. The dependency on both the size of the system and of the basis set, contradicts the idea of a universal IPEA shift which is able to compensate for systematic CASPT2 errors in the calculation of excited states.},
date-added = {2022-03-24 21:59:07 +0100},
date-modified = {2022-03-24 21:59:07 +0100}
}
@article{Zobel_2021,
title = {The Quest to Simulate Excited-State Dynamics of Transition Metal Complexes},
author = {Zobel, J. Patrick and Gonz{\'a}lez, Leticia},
