#+TITLE: TREX Configuration file All the quantities are saved in atomic units. The dimensions of the arrays in the tables below are given in column-major order (as in Fortran), and the ordering of the dimensions is reversed in the produces JSON configuration file as the library is written in C. #+begin_src python :tangle trex.json { #+end_src * Metadata As we expect our files to be archived in open-data repositories, we need to give the possibility to the users to store some metadata inside the files. We propose to store the list of names of the codes which have participated to the creation of the file, a list of authors of the file, and a textual description. #+NAME: metadata | ~code_num~ | ~int~ | | Number of codes used to produce the file | | ~code~ | ~str~ | ~(metadata.code_num)~ | Names of the codes used | | ~author_num~ | ~int~ | | Number of authors of the file | | ~author~ | ~str~ | ~(metadata.author_num)~ | Names of the authors of the file | | ~description~ | ~str~ | | Text describing the content of file | #+CALL: json(data=metadata, title="metadata") #+RESULTS: :results: #+begin_src python :tangle trex.json "metadata": { "code_num" : [ "int", [] ] , "code " : [ "str", [ "metadata.code_num" ] ] , "author_num" : [ "int", [] ] , "author" : [ "str", [ "metadata.author_num" ] ] , "description" : [ "str", [] ] } , #+end_src :end: * Electron We consider wave functions expressed in the spin-free formalism, where the number of \uparrow and \downarrow electrons is fixed. #+NAME:electron | ~up_num~ | ~int~ | Number of \uparrow-spin electrons | | ~dn_num~ | ~int~ | Number of \downarrow-spin electrons | #+CALL: json(data=electron, title="electron") #+RESULTS: :results: #+begin_src python :tangle trex.json "electron": { "up_num" : [ "int", [] ] , "dn_num" : [ "int", [] ] } , #+end_src :end: * Nucleus The nuclei are considered as fixed point charges. Coordinates are given in Cartesian $(x,y,z)$ format. #+NAME: nucleus | ~num~ | ~int~ | | Number of nuclei | | ~charge~ | ~float~ | ~(nucleus.num)~ | Charges of the nuclei | | ~coord~ | ~float~ | ~(3,nucleus.num)~ | Coordinates of the atoms | | ~label~ | ~str~ | ~(nucleus.num)~ | Atom labels | | ~point_group~ | ~str~ | | Symmetry point group | #+CALL: json(data=nucleus, title="nucleus") #+RESULTS: :results: #+begin_src python :tangle trex.json "nucleus": { "num" : [ "int" , [] ] , "charge" : [ "float", [ "nucleus.num" ] ] , "coord" : [ "float", [ "nucleus.num", "3" ] ] , "label" : [ "str" , [ "nucleus.num" ] ] , "point_group" : [ "str" , [] ] } , #+end_src :end: * TODO Effective core potentials An effective core potential (ECP) $V_A^{\text{pp}}$ replacing the core electrons of atom $A$ is the sum of a local component $V_A^{\text{l}}$ and a non-local component $V_A^{\text{nl}}$. The local component is given by \[ \hat{V}_A^{\text{l}}(r) = -\frac{Z_A^{\text{eff}}}{r} + \frac{Z_A^{\text{eff}}}{r}\, \exp\left( -\alpha_A\, r^2\right) + Z_{\text{eff}}\, \alpha_A\, r\, \exp\left( -\beta_A\, r^2\right) + \gamma_A \exp\left( -\delta_A\, r^2\right), \] and the component obtained after localizing the non-local operator is \[ \hat{V}_A^{\text{nl}}(r) = \zeta_A\, \exp\left( -\eta_A\, r^2\right) |0\rangle \langle 0| + \mu_A \, \exp\left( -\nu_A \, r^2\right) |1\rangle \langle 1| \] where $r=|\mathbf{r-R}_A|$ is the distance to the nucleus on which the potential is centered, $Z_A^{\text{eff}}$ is the effective charge due to the removed electrons, $|0\rangle \langle 0|$ and $|1\rangle \langle 1|$ are projections over zero and one principal angular momenta, respectively (generalization to higher angular momenta is straightforward), and all the parameters labeled by Greek letters are parameters. - $\hat{V}_\text{ecp,l} = \sum_A \hat{V}_A^{\text{l}}$ : local component - $\hat{V}_\text{ecp,nl} = \sum_A \hat{V}_A^{\text{nl}}$ : non-local component #+NAME: ecp | ~lmax_plus_1~ | ~int~ | ~(nucleus.num)~ | $l_{\max} + 1$ | | ~z_core~ | ~float~ | ~(nucleus.num)~ | Charges to remove | | ~local_n~ | ~int~ | ~(nucleus.num)~ | Number of local function | | ~local_num_n_max~ | ~int~ | | Maximum value of ~local_n~ | | ~local_exponent~ | ~float~ | ~(ecp.local_num_n_max, nucleus.num)~ | | | ~local_coef~ | ~float~ | ~(ecp.local_num_n_max, nucleus.num)~ | | | ~local_power~ | ~int~ | ~(ecp.local_num_n_max, nucleus.num)~ | | | ~non_local_n~ | ~int~ | ~(nucleus.num)~ | | | ~non_local_num_n_max~ | ~int~ | | | | ~non_local_exponent~ | ~float~ | ~(ecp.non_local_num_n_max, nucleus.num)~ | | | ~non_local_coef~ | ~float~ | ~(ecp.non_local_num_n_max, nucleus.num)~ | | | ~non_local_power~ | ~int~ | ~(ecp.non_local_num_n_max, nucleus.num)~ | | #+CALL: json(data=ecp, title="ecp") #+RESULTS: :results: #+begin_src python :tangle trex.json "ecp": { "lmax_plus_1" : [ "int" , [ "nucleus.num" ] ] , "z_core" : [ "float", [ "nucleus.num" ] ] , "local_n" : [ "int" , [ "nucleus.num" ] ] , "local_num_n_max" : [ "int" , [] ] , "local_exponent" : [ "float", [ "nucleus.num", "ecp.local_num_n_max" ] ] , "local_coef" : [ "float", [ "nucleus.num", "ecp.local_num_n_max" ] ] , "local_power" : [ "int" , [ "nucleus.num", "ecp.local_num_n_max" ] ] , "non_local_n" : [ "int" , [ "nucleus.num" ] ] , "non_local_num_n_max" : [ "int" , [] ] , "non_local_exponent" : [ "float", [ "nucleus.num", "ecp.non_local_num_n_max" ] ] , "non_local_coef" : [ "float", [ "nucleus.num", "ecp.non_local_num_n_max" ] ] , "non_local_power" : [ "int" , [ "nucleus.num", "ecp.non_local_num_n_max" ] ] } , #+end_src :end: * Basis set We consider here basis functions centered on nuclei. Hence, we enable the possibility to define \emph{dummy atoms} to place basis functions in random positions. The atomic basis set is defined as a list of shells. Each shell $s$ is centered on a center $A$, possesses a given angular momentum $l$ and a radial function $R_s$. The radial function is a linear combination of $N_{\text{prim}}$ /primitive/ functions that can be of type Slater ($p=1$) or Gaussian ($p=2$), parameterized by exponents $\gamma_{ks}$ and coefficients $a_{ks}$: \[ R_s(\mathbf{r}) = \mathcal{N}_s \vert\mathbf{r}-\mathbf{R}_A\vert^{n_s} \sum_{k=1}^{N_{\text{prim}}} a_{ks} \exp \left( - \gamma_{ks} \vert \mathbf{r}-\mathbf{R}_A \vert ^p \right). \] In the case of Gaussian functions, $n_s$ is always zero. The normalization factor $\mathcal{N}_s$ ensures that all the functions of the shell are normalized to unity. As this normalization requires the ability to compute overlap integrals, the normalization factors should be written in the file to ensure that the file is self-contained and does not require the client program to have the ability to compute such integrals. #+NAME: basis | ~type~ | ~str~ | | Type of basis set: "Gaussian" or "Slater" | | ~shell_num~ | ~int~ | | Total Number of shells | | ~shell_center~ | ~int~ | ~(basis.shell_num)~ | Nucleus on which the shell is centered | | ~shell_ang_mom~ | ~int~ | ~(basis.shell_num)~ | Angular momentum ~0:S, 1:P, 2:D, ...~ | | ~shell_prim_num~ | ~int~ | ~(basis.shell_num)~ | Number of primitives in the shell | | ~shell_factor~ | ~float~ | ~(basis.shell_num)~ | Normalization factor of the shell | | ~prim_index~ | ~int~ | ~(basis.shell_num)~ | Index of the first primitive in the complete list | | ~prim_num~ | ~int~ | | Total number of primitives | | ~exponent~ | ~float~ | ~(basis.prim_num)~ | Exponents of the primitives | | ~coefficient~ | ~float~ | ~(basis.prim_num)~ | Coefficients of the primitives | #+CALL: json(data=basis, title="basis") #+RESULTS: :results: #+begin_src python :tangle trex.json "basis": { "type" : [ "str" , [] ] , "shell_num" : [ "int" , [] ] , "shell_factor" : [ "float", [ "basis.shell_num" ] ] , "shell_center" : [ "int" , [ "basis.shell_num" ] ] , "shell_ang_mom" : [ "int" , [ "basis.shell_num" ] ] , "shell_prim_num" : [ "int" , [ "basis.shell_num" ] ] , "prim_index" : [ "int" , [ "basis.shell_num" ] ] , "prim_num" : [ "int" , [] ] , "exponent" : [ "float", [ "basis.prim_num" ] ] , "coefficient" : [ "float", [ "basis.prim_num" ] ] } , #+end_src :end: * Atomic orbitals Going from the atomic basis set to AOs implies a systematic construction of all the angular functions of each shell. We consider two cases for the angular functions: the real-valued spherical harmonics, and the polynomials in Cartesian coordinates. In the case of spherical harmonics, the AOs are ordered in increasing magnetic quantum number ($-l \le m \le l$), and in the case of polynomials we impose the canonical ordering of the Libint2 library, i.e \begin{eqnarray} p & : & p_x, p_y, p_z \nonumber \\ d & : & d_{xx}, d_{xy}, d_{xz}, d_{yy}, d_{yz}, d_{zz} \nonumber \\ f & : & f_{xxx}, f_{xxy}, f_{xxz}, f_{xyy}, f_{xyz}, f_{xzz}, f_{yyy}, f_{yyz}, f_{yzz}, …f_{zzz} \nonumber \\ {\rm etc.} \nonumber \end{eqnarray} AOs are defined as \[ \chi_i (\mathbf{r}) = \mathcal{N}_i\, P_{\eta(i)}(\mathbf{r})\, R_{\theta(i)} (\mathbf{r}) \] where $i$ is the atomic orbital index, $P$ encodes for either the polynomials or the spherical harmonics, $\theta(i)$ returns the shell on which the AO is expanded, and $\eta(i)$ denotes which angular function is chosen. $\mathcal{N}_i$ is a normalization factor that enables the possibility to have different normalization coefficients within a shell, as in the GAMESS convention where $\mathcal{N}_{x^2} \ne \mathcal{N}_{xy}$ because \[ \left[ \iiint \left(x-X_A \right)^2 R_{\theta(i)} (\mathbf{r}) dx\, dy\, dz \right]^{-1/2} \ne \left[ \iiint \left( x-X_A \right) \left( y-Y_A \right) R_{\theta(i)} (\mathbf{r}) dx\, dy\, dz \right]^{-1/2}. \] In such a case, one should set the normalization of the shell (in the [[Basis set][Basis set]] section) to $\mathcal{N}_{z^2}$, which is the normalization factor of the atomic orbitals in spherical coordinates. The normalization factor of the $xy$ function which should be introduced here should be $\frac{\mathcal{N}_{xy}}{\mathcal{N}_{z^2}}$. #+NAME: ao | ~cartesian~ | ~int~ | | ~1~: true, ~0~: false | | ~num~ | ~int~ | | Total number of atomic orbitals | | ~shell~ | ~int~ | ~(ao.num)~ | basis set shell for each AO | | ~normalization~ | ~float~ | ~(ao.num)~ | Normalization factors | #+CALL: json(data=ao, title="ao") #+RESULTS: :results: #+begin_src python :tangle trex.json "ao": { "cartesian" : [ "int" , [] ] , "num" : [ "int" , [] ] , "shell" : [ "int" , [ "ao.num" ] ] , "normalization" : [ "float", [ "ao.num" ] ] } , #+end_src :end: ** One-electron integrals :PROPERTIES: :CUSTOM_ID: ao_one_e :END: - \[ \hat{V}_{\text{ne}} = \sum_{A=1}^{N_\text{nucl}} \sum_{i=1}^{N_\text{elec}} \frac{-Z_A }{\vert \mathbf{R}_A - \mathbf{r}_i \vert} \] : electron-nucleus attractive potential, - \[ \hat{T}_{\text{e}} = \sum_{i=1}^{N_\text{elec}} -\frac{1}{2}\hat{\Delta}_i \] : electronic kinetic energy - $\hat{h} = \hat{T}_\text{e} + \hat{V}_\text{ne} + \hat{V}_\text{ecp,l} + \hat{V}_\text{ecp,nl}$ : core electronic Hamiltonian The one-electron integrals for a one-electron operator $\hat{O}$ are \[ \langle p \vert \hat{O} \vert q \rangle \], returned as a matrix over atomic orbitals. #+NAME: ao_1e_int | ~overlap~ | ~float~ | ~(ao.num, ao.num)~ | $\langle p \vert q \rangle$ | | ~kinetic~ | ~float~ | ~(ao.num, ao.num)~ | $\langle p \vert \hat{T}_e \vert q \rangle$ | | ~potential_n_e~ | ~float~ | ~(ao.num, ao.num)~ | $\langle p \vert \hat{V}_{\text{ne}} \vert q \rangle$ | | ~ecp_local~ | ~float~ | ~(ao.num, ao.num)~ | $\langle p \vert \hat{V}_{\text{ecp,l} \vert q \rangle$ | | ~ecp_non_local~ | ~float~ | ~(ao.num, ao.num)~ | $\langle p \vert \hat{V}_{\text{ecp,nl} \vert q \rangle$ | | ~core_hamiltonian~ | ~float~ | ~(ao.num, ao.num)~ | $\langle p \vert \hat{h} \vert q \rangle$ | #+CALL: json(data=ao_1e_int, title="ao_1e_int") #+RESULTS: :results: #+begin_src python :tangle trex.json "ao_1e_int": { "overlap" : [ "float", [ "ao.num", "ao.num" ] ] , "kinetic" : [ "float", [ "ao.num", "ao.num" ] ] , "potential_n_e" : [ "float", [ "ao.num", "ao.num" ] ] , "ecp_local" : [ "float", [ "ao.num", "ao.num" ] ] , "ecp_non_local" : [ "float", [ "ao.num", "ao.num" ] ] , "core_hamiltonian" : [ "float", [ "ao.num", "ao.num" ] ] } , #+end_src :end: ** Two-electron integrals :PROPERTIES: :CUSTOM_ID: ao_two_e :END: The two-electron integrals for a two-electron operator $\hat{O}$ are \[ \langle p q \vert \hat{O} \vert r s \rangle \] in physicists notation or \[ ( pr \vert \hat{O} \vert qs ) \] in chemists notation, where $p,q,r,s$ are indices over atomic orbitals. Functions are provided to get the indices in physicists or chemists notation. # TODO: Physicist / Chemist functions - \[ \hat{W}_{\text{ee}} = \sum_{i=2}^{N_\text{elec}} \sum_{j=1}^{i-1} \frac{1}{\vert \mathbf{r}_i - \mathbf{r}_j \vert} \] : electron-electron repulsive potential operator. - \[ \hat{W}^{lr}_{\text{ee}} = \sum_{i=2}^{N_\text{elec}} \sum_{j=1}^{i-1} \frac{\text{erf}(\vert \mathbf{r}_i - \mathbf{r}_j \vert)}{\vert \mathbf{r}_i - \mathbf{r}_j \vert} \] : electron-electron long range potential #+NAME: ao_2e_int | ~eri~ | ~float sparse~ | ~(ao.num, ao.num, ao.num, ao.num)~ | Electron repulsion integrals | | ~eri_lr~ | ~float sparse~ | ~(ao.num, ao.num, ao.num, ao.num)~ | Long-range Electron repulsion integrals | #+CALL: json(data=ao_2e_int, title="ao_2e_int") #+RESULTS: :results: #+begin_src python :tangle trex.json "ao_2e_int": { "eri" : [ "float sparse", [ "ao.num", "ao.num", "ao.num", "ao.num" ] ] , "eri_lr" : [ "float sparse", [ "ao.num", "ao.num", "ao.num", "ao.num" ] ] } , #+end_src :end: * Molecular orbitals #+NAME: mo | ~type~ | ~str~ | | String identify the set of MOs | | ~num~ | ~int~ | | Number of MOs | | ~coefficient~ | ~float~ | ~(ao.num, mo.num)~ | MO coefficients | | ~class~ | ~str~ | ~(mo.num)~ | Core, Inactive, Active, Virtual, Deleted | | ~symmetry~ | ~str~ | ~(mo.num)~ | Symmetry in the point group | | ~occupation~ | ~float~ | ~(mo.num)~ | Occupation number | #+CALL: json(data=mo, title="mo") #+RESULTS: :results: #+begin_src python :tangle trex.json "mo": { "type" : [ "str" , [] ] , "num" : [ "int" , [] ] , "coefficient" : [ "float", [ "mo.num", "ao.num" ] ] , "class" : [ "str" , [ "mo.num" ] ] , "symmetry" : [ "str" , [ "mo.num" ] ] , "occupation" : [ "float", [ "mo.num" ] ] } , #+end_src :end: ** One-electron integrals The operators as the same as those defined in the [[ao_one_e][AO one-electron integrals section]]. Here, the integrals are given in the basis of molecular orbitals. #+NAME: mo_1e_int | ~overlap~ | ~float~ | ~(mo.num, mo.num)~ | $\langle i \vert j \rangle$ | | ~kinetic~ | ~float~ | ~(mo.num, mo.num)~ | $\langle i \vert \hat{T}_e \vert j \rangle$ | | ~potential_n_e~ | ~float~ | ~(mo.num, mo.num)~ | $\langle i \vert \hat{V}_{\text{ne}} \vert j \rangle$ | | ~ecp_local~ | ~float~ | ~(mo.num, mo.num)~ | $\langle i \vert \hat{V}_{\text{ecp,l} \vert j \rangle$ | | ~ecp_non_local~ | ~float~ | ~(mo.num, mo.num)~ | $\langle i \vert \hat{V}_{\text{ecp,nl} \vert j \rangle$ | | ~core_hamiltonian~ | ~float~ | ~(mo.num, mo.num)~ | $\langle i \vert \hat{h} \vert j \rangle$ | #+CALL: json(data=mo_1e_int, title="mo_1e_int") #+RESULTS: :results: #+begin_src python :tangle trex.json "mo_1e_int": { "overlap" : [ "float", [ "mo.num", "mo.num" ] ] , "kinetic" : [ "float", [ "mo.num", "mo.num" ] ] , "potential_n_e" : [ "float", [ "mo.num", "mo.num" ] ] , "ecp_local" : [ "float", [ "mo.num", "mo.num" ] ] , "ecp_non_local" : [ "float", [ "mo.num", "mo.num" ] ] , "core_hamiltonian" : [ "float", [ "mo.num", "mo.num" ] ] } , #+end_src :end: ** Two-electron integrals The operators as the same as those defined in the [[ao_two_e][AO two-electron integrals section]]. Here, the integrals are given in the basis of molecular orbitals. #+NAME: mo_2e_int | ~eri~ | ~float sparse~ | ~(mo.num, mo.num, mo.num, mo.num)~ | Electron repulsion integrals | | ~eri_lr~ | ~float sparse~ | ~(mo.num, mo.num, mo.num, mo.num)~ | Long-range Electron repulsion integrals | #+CALL: json(data=mo_2e_int, title="mo_2e_int") #+RESULTS: :results: #+begin_src python :tangle trex.json "mo_2e_int": { "eri" : [ "float sparse", [ "mo.num", "mo.num", "mo.num", "mo.num" ] ] , "eri_lr" : [ "float sparse", [ "mo.num", "mo.num", "mo.num", "mo.num" ] ] } , #+end_src :end: * TODO Slater determinants * TODO Reduced density matrices #+NAME: rdm | ~one_e~ | ~float~ | ~(mo.num, mo.num)~ | | ~one_e_up~ | ~float~ | ~(mo.num, mo.num)~ | | ~one_e_dn~ | ~float~ | ~(mo.num, mo.num)~ | | ~two_e~ | ~float sparse~ | ~(mo.num, mo.num, mo.num, mo.num)~ | #+CALL: json(data=rdm, title="rdm", last=1) #+RESULTS: :results: #+begin_src python :tangle trex.json "rdm": { "one_e" : [ "float" , [ "mo.num", "mo.num" ] ] , "one_e_up" : [ "float" , [ "mo.num", "mo.num" ] ] , "one_e_dn" : [ "float" , [ "mo.num", "mo.num" ] ] , "two_e" : [ "float sparse", [ "mo.num", "mo.num", "mo.num", "mo.num" ] ] } #+end_src :end: * Appendix :noexport: ** Python script from table to json #+NAME: json #+begin_src python :var data=nucleus title="nucleus" last=0 :results output drawer print("""#+begin_src python :tangle trex.json""") print(""" "%s": {"""%(title)) indent = " " f1 = 0 ; f2 = 0 ; f3 = 0 for line in data: line = [ x.replace("~","") for x in line ] name = '"'+line[0]+'"' typ = '"'+line[1]+'"' dims = line[2] if '(' in dims: dims = dims.strip()[1:-1] dims = [ '"'+x.strip()+'"' for x in dims.split(',') ] dims = "[ " + ", ".join(dims) + " ]" else: dims = "[ ]" f1 = max(f1, len(name)) f2 = max(f2, len(typ)) f3 = max(f3, len(dims)) fmt = "%%s%%%ds : [ %%%ds, %%%ds ]" % (f1, f2, f3) for line in data: line = [ x.replace("~","") for x in line ] name = '"'+line[0]+'"' typ = '"'+line[1]+'"' dims = line[2] if '(' in dims: dims = dims.strip()[1:-1] dims = [ '"'+x.strip()+'"' for x in dims.split(',') ] dims.reverse() dims = "[ " + ", ".join(dims) + " ]" else: if dims.strip() != "": dims = "ERROR" else: dims = "[]" buffer = fmt % (indent, name, typ.ljust(f2), dims.ljust(f3)) indent = " , " print(buffer) if last == 0: print(" } ,") else: print(" }") print("""#+end_src""") #+end_src #+begin_src python :tangle trex.json :results output drawer } #+end_src