JCP template

Manuscript/Ec.tex

@@ -1,4 +1,4 @@
-\documentclass[aps,prb,reprint,noshowkeys,superscriptaddress]{revtex4-1}
+\documentclass[aip,jcp,reprint,noshowkeys,superscriptaddress,floatfix]{revtex4-1}
 \usepackage{graphicx,dcolumn,bm,xcolor,microtype,multirow,amscd,amsmath,amssymb,amsfonts,physics,wrapfig,txfonts,siunitx}
 \usepackage[version=4]{mhchem}
 
@@ -142,8 +142,7 @@ Accordingly, the SCI+PT2 family of methods performs a sparse exploration of the
 Although the formal scaling of such algorithms remains exponential, the prefactor is greatly reduced which explains their current attractiveness in the electronic structure community thanks to their much wider applicability than their standard FCI parent.
 Note that, very recently, several groups \cite{Aroeira_2021,Lee_2021,Magoulas_2021} have coupled CC and SCI methods via the externally-corrected CC methodology, \cite{Paldus_2017} showing promising performances for weakly and strongly correlated systems.
 
-A rather different strategy in order to reach the holy grail FCI limit is to resort to M{\o}ller-Plesset (MP) perturbation theory, \cite{Moller_1934}
-whose popularity originates from its black-box nature, size-extensivity, and relatively low computational requirement, making it easily applied to a broad range of molecular systems. 
+A rather different strategy in order to reach the holy grail FCI limit is to resort to M{\o}ller-Plesset (MP) perturbation theory, \cite{Moller_1934} whose popularity originates from its black-box nature, size-extensivity, and relatively low computational requirement, making it easily applied to a broad range of molecular systems. 
 Again, at least in theory, one can obtain the exact energy of the system by ramping up the degree of the perturbative series. \cite{Marie_2021a}
 The second-order M{\o}ller-Plesset (MP2) method \cite{Moller_1934} [which scales as $\order*{\Norb^{5}}$] has been broadly adopted in quantum chemistry for several decades, and is now included in the increasingly popular double-hybrid functionals \cite{Grimme_2006} alongside exact exchange. 
 Its higher-order variants [MP3, \cite{Pople_1976} MP4, \cite{Krishnan_1980} MP5, \cite{Kucharski_1989} and MP6 \cite{He_1996a,He_1996b} which scale as $\order*{\Norb^{6}}$, $\order*{\Norb^{7}}$, $\order*{\Norb^{8}}$, and $\order*{\Norb^{9}}$ respectively] have been investigated much more scarcely.
@@ -704,8 +703,7 @@ Importantly here, one notices that MP4 [which scales as $\order*{N^7}$] is syste
 %%%%%%%%%%%%%%%%%%%%%%%%%
 Using the SCI algorithm named \textit{Configuration Interaction using a Perturbative Selection made Iteratively} (CIPSI), we have produced FCI-quality frozen-core correlation energies for twelve cyclic molecules (see Fig.~\ref{fig:mol}) in the correlation-consistent double-$\zeta$ Dunning basis set (cc-pVDZ).
 These estimates, which are likely accurate to a few tenths of a millihartree, have been obtained by extrapolating CIPSI energies to the FCI limit based on a set of orbitals obtained by minimizing the CIPSI variational energy.
-Using energetically optimized orbitals, one can reduce the size of the variational space by one order of magnitude for the same variational energy as compared
-to natural orbitals.
+Using energetically optimized orbitals, one can reduce the size of the variational space by one order of magnitude for the same variational energy as compared to natural orbitals.
 
 Thanks to these reference FCI energies, we have then benchmarked three families of popular electronic structure methods: i) the MP perturbation series up to fifth-order (MP2, MP3, MP4, and MP5), ii) the approximate CC series CC2, CC3, and CC4, and iii) the ``complete'' CC series CCSD, CCSDT, and CCSDTQ.
 With a $\order*{N^7}$ scaling, MP4 provides an interesting accuracy/cost ratio for this particular set of weakly correlated systems, while MP5 systematically worsen the perturbative estimates of the correlation energy.