Source code for iodata.formats.fchk

# IODATA is an input and output module for quantum chemistry.
# Copyright (C) 2011-2019 The IODATA Development Team
#
# This file is part of IODATA.
#
# IODATA is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 3
# of the License, or (at your option) any later version.
#
# IODATA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>
# --
"""Gaussian FCHK file format."""

from collections.abc import Iterator
from fnmatch import fnmatch
from typing import Optional, TextIO

import numpy as np
from numpy.typing import NDArray

from ..basis import HORTON2_CONVENTIONS, MolecularBasis, Shell, convert_conventions
from ..docstrings import document_dump_one, document_load_many, document_load_one
from ..iodata import IOData
from ..orbitals import MolecularOrbitals
from ..utils import DumpError, LineIterator, LoadError, PrepareDumpError, amu

__all__ = []


PATTERNS = ["*.fchk", "*.fch"]


CONVENTIONS = {
    (9, "p"): HORTON2_CONVENTIONS[(9, "p")],
    (8, "p"): HORTON2_CONVENTIONS[(8, "p")],
    (7, "p"): HORTON2_CONVENTIONS[(7, "p")],
    (6, "p"): HORTON2_CONVENTIONS[(6, "p")],
    (5, "p"): HORTON2_CONVENTIONS[(5, "p")],
    (4, "p"): HORTON2_CONVENTIONS[(4, "p")],
    (3, "p"): HORTON2_CONVENTIONS[(3, "p")],
    (2, "p"): HORTON2_CONVENTIONS[(2, "p")],
    (0, "c"): ["1"],
    (1, "c"): ["x", "y", "z"],
    (2, "c"): ["xx", "yy", "zz", "xy", "xz", "yz"],
    (3, "c"): ["xxx", "yyy", "zzz", "xyy", "xxy", "xxz", "xzz", "yzz", "yyz", "xyz"],
    (4, "c"): HORTON2_CONVENTIONS[(4, "c")][::-1],
    (5, "c"): HORTON2_CONVENTIONS[(5, "c")][::-1],
    (6, "c"): HORTON2_CONVENTIONS[(6, "c")][::-1],
    (7, "c"): HORTON2_CONVENTIONS[(7, "c")][::-1],
    (8, "c"): HORTON2_CONVENTIONS[(8, "c")][::-1],
    (9, "c"): HORTON2_CONVENTIONS[(9, "c")][::-1],
}


[docs] @document_load_one( "Gaussian Formatted Checkpoint", [ "atcharges", "atcoords", "atnums", "atcorenums", "lot", "mo", "obasis", "obasis_name", "run_type", "title", ], ["energy", "atfrozen", "atgradient", "athessian", "atmasses", "one_rdms", "extra", "moments"], ) def load_one(lit: LineIterator) -> dict: """Do not edit this docstring. It will be overwritten.""" fchk = _load_fchk_low( lit, [ "Number of electrons", "Number of basis functions", "Number of alpha electrons", "Number of beta electrons", "Atomic numbers", "Current cartesian coordinates", "Real atomic weights", "Shell types", "Shell to atom map", "Shell to atom map", "Number of primitives per shell", "Primitive exponents", "Contraction coefficients", "P(S=P) Contraction coefficients", "Alpha Orbital Energies", "Alpha MO coefficients", "Beta Orbital Energies", "Beta MO coefficients", "Total Energy", "Nuclear charges", "Total SCF Density", "Spin SCF Density", "Total MP2 Density", "Spin MP2 Density", "Total MP3 Density", "Spin MP3 Density", "Total CC Density", "Spin CC Density", "Total CI Density", "Spin CI Density", "Mulliken Charges", "ESP Charges", "NPA Charges", "MBS Charges", "Type 6 Charges", "Type 7 Charges", "Polarizability", "Dipole Moment", "Quadrupole Moment", "Cartesian Gradient", "Cartesian Force Constants", "MicOpt", ], ) # A) Load a bunch of simple things result = { "title": fchk["title"], # if "Total Energy" is not present in FCHk, None is returned. "energy": fchk.get("Total Energy", None), "lot": fchk["lot"].lower(), "obasis_name": fchk["obasis_name"].lower(), "atcoords": fchk["Current cartesian coordinates"].reshape(-1, 3), "atnums": fchk["Atomic numbers"], "atcorenums": fchk["Nuclear charges"], } atmasses = fchk.get("Real atomic weights") if atmasses is not None: result["atmasses"] = atmasses * amu atgradient = fchk.get("Cartesian Gradient") if atgradient is not None: result["atgradient"] = atgradient.reshape(-1, 3) athessian = fchk.get("Cartesian Force Constants") if athessian is not None: result["athessian"] = _triangle_to_dense(athessian) atfrozen = fchk.get("MicOpt") if atfrozen is not None: result["atfrozen"] = atfrozen == -2 run_types = {"SP": "energy", "FOpt": "opt", "Scan": "scan", "Freq": "freq"} run_type = run_types.get(fchk["command"]) if run_type is not None: result["run_type"] = run_type # B) Load the orbital basis set shell_types = fchk["Shell types"] shell_map = fchk["Shell to atom map"] - 1 nprims = fchk["Number of primitives per shell"] exponents = fchk["Primitive exponents"] ccoeffs_level1 = fchk["Contraction coefficients"] ccoeffs_level2 = fchk.get("P(S=P) Contraction coefficients") shells = [] counter = 0 # First loop over all shells for i, n in enumerate(nprims): if shell_types[i] == -1: # Special treatment for SP shell type shells.append( Shell( shell_map[i], [0, 1], ["c", "c"], exponents[counter : counter + n], np.stack( [ ccoeffs_level1[counter : counter + n], ccoeffs_level2[counter : counter + n], ], axis=1, ), ) ) else: shells.append( Shell( shell_map[i], [abs(shell_types[i])], ["p" if shell_types[i] < 0 else "c"], exponents[counter : counter + n], ccoeffs_level1[counter : counter + n][:, np.newaxis], ) ) counter += n del shell_map del shell_types del nprims del exponents result["obasis"] = MolecularBasis(shells, CONVENTIONS, "L2") nbasis = fchk["Number of basis functions"] # C) Load density matrices one_rdms = {} _load_dm("Total SCF Density", fchk, one_rdms, "scf") _load_dm("Spin SCF Density", fchk, one_rdms, "scf_spin") # only one of the lots should be present, hence using the same key for lot in "MP2", "MP3", "CC", "CI": _load_dm(f"Total {lot} Density", fchk, one_rdms, "post_scf_ao") _load_dm(f"Spin {lot} Density", fchk, one_rdms, "post_scf_spin_ao") if one_rdms: result["one_rdms"] = one_rdms # D) Load the wavefunction # Load orbitals nalpha = fchk["Number of alpha electrons"] nbeta = fchk["Number of beta electrons"] if nalpha < 0 or nbeta < 0 or nalpha + nbeta <= 0: raise LoadError("The number of electrons is not positive.", lit) if nalpha < nbeta: raise LoadError(f"n_alpha={nalpha} < n_beta={nbeta} is invalid.", lit) norba = fchk["Alpha Orbital Energies"].shape[0] mo_coeffs = np.copy(fchk["Alpha MO coefficients"].reshape(norba, nbasis).T) mo_energies = np.copy(fchk["Alpha Orbital Energies"]) if "Beta Orbital Energies" in fchk: # unrestricted norbb = fchk["Beta Orbital Energies"].shape[0] mo_coeffs_b = np.copy(fchk["Beta MO coefficients"].reshape(norbb, nbasis).T) mo_coeffs = np.concatenate((mo_coeffs, mo_coeffs_b), axis=1) mo_energies = np.concatenate((mo_energies, np.copy(fchk["Beta Orbital Energies"])), axis=0) mo_occs = np.zeros(norba + norbb) mo_occs[:nalpha] = 1.0 mo_occs[norba : norba + nbeta] = 1.0 mo = MolecularOrbitals("unrestricted", norba, norbb, mo_occs, mo_coeffs, mo_energies) else: # restricted closed-shell and open-shell mo_occs = np.zeros(norba) mo_occs[:nalpha] = 1.0 mo_occs[:nbeta] = 2.0 # delete dm_full_scf because it is known to be buggy if nalpha != nbeta and "one_rdms" in result and "scf" in result["one_rdms"]: result["one_rdms"].pop("scf") mo = MolecularOrbitals("restricted", norba, norba, mo_occs, mo_coeffs, mo_energies) result["mo"] = mo # E) Load properties if "Polarizability" in fchk: result["extra"] = {"polarizability_tensor": _triangle_to_dense(fchk["Polarizability"])} moments = {} if "Dipole Moment" in fchk: moments[(1, "c")] = fchk["Dipole Moment"] if "Quadrupole Moment" in fchk: # Convert to alphabetical ordering: xx, xy, xz, yy, yz, zz moments[(2, "c")] = fchk["Quadrupole Moment"][[0, 3, 4, 1, 5, 2]] if moments: result["moments"] = moments atcharges = {} if "Mulliken Charges" in fchk: atcharges["mulliken"] = fchk["Mulliken Charges"] if "ESP Charges" in fchk: atcharges["esp"] = fchk["ESP Charges"] if "NPA Charges" in fchk: atcharges["npa"] = fchk["NPA Charges"] if "MBS Charges" in fchk: atcharges["mbs"] = fchk["MBS Charges"] if "Type 6 Charges" in fchk: atcharges["hirshfeld"] = fchk["Type 6 Charges"] if "Type 7 Charges" in fchk: atcharges["cm5"] = fchk["Type 7 Charges"] if atcharges: result["atcharges"] = atcharges return result
LOAD_MANY_NOTES = """ Trajectories from a Gaussian optimization, relaxed scan or IRC calculation are written in groups of frames, called "points" in the Gaussian world, e.g. to discrimininate between different values of the constraint in a relaxed geometry. In most cases, e.g. IRC or conventional optimization, there is only one "point". Within one "point", one can have multiple geometries and their properties. This information is stored in the ``extra`` attribute: - ``ipoint`` is the counter for a point - ``npoint`` is the total number of points. - ``istep`` is the counter within one "point" - ``nstep`` is the total number of geometries within in a "point". - ``reaction_coordinate`` is only present in case of an IRC calculation. """
[docs] @document_load_many( "XYZ", ["atcoords", "atgradient", "atnums", "atcorenums", "energy", "extra", "title"], [], {}, LOAD_MANY_NOTES, ) def load_many(lit: LineIterator) -> Iterator[dict]: """Do not edit this docstring. It will be overwritten.""" fchk = _load_fchk_low( lit, [ "Atomic numbers", "Current cartesian coordinates", "Nuclear charges", "IRC *", "Optimization *", "Opt point *", ], ) # Determine the type of calculation: IRC or Optimization if "IRC Number of geometries" in fchk: prefix = "IRC point" nsteps = fchk["IRC Number of geometries"] elif "Optimization Number of geometries" in fchk: prefix = "Opt point" nsteps = fchk["Optimization Number of geometries"] else: raise LoadError("Cannot find IRC or Optimization trajectory in FCHK file.", lit) natom = fchk["Atomic numbers"].size for ipoint, nstep in enumerate(nsteps): results_geoms = fchk[f"{prefix} {ipoint + 1:7d} Results for each geome"] trajectory = list( zip( results_geoms[::2], results_geoms[1::2], fchk[f"{prefix} {ipoint + 1:7d} Geometries"].reshape(-1, natom, 3), fchk[f"{prefix} {ipoint + 1:7d} Gradient at each geome"].reshape(-1, natom, 3), ) ) assert len(trajectory) == nstep for istep, (energy, recor, atcoords, gradients) in enumerate(trajectory): data = { "title": fchk["title"], "atnums": fchk["Atomic numbers"], "atcorenums": fchk["Nuclear charges"], "energy": energy, "atcoords": atcoords, "atgradient": gradients, "extra": { "ipoint": ipoint, "npoint": len(nsteps), "istep": istep, "nstep": nstep, }, } if prefix == "IRC point": data["extra"]["reaction_coordinate"] = recor yield data
def _load_fchk_low(lit: LineIterator, label_patterns: Optional[list[str]] = None) -> dict: """Read selected fields from a formatted checkpoint file. Parameters ---------- lit The line iterator to read the data from. label_patterns A list of Unix shell-style wildcard patterns of labels to read. Returns ------- A dictionary containing data read from the FCHK file. Keys are the field names and values are either scalar or array data. Arrays are always one-dimensional. """ # Read the two-line header result = {"title": next(lit).strip()} words = next(lit).split() if len(words) == 3: result["command"], result["lot"], result["obasis_name"] = words elif len(words) == 2: result["command"], result["lot"] = words else: raise LoadError("The second line of the FCHK file should contain two or three words.", lit) while True: try: label, value = _load_fchk_field(lit, label_patterns) except StopIteration: # We always read until the end of the file. break result[label] = value return result def _load_fchk_field(lit: LineIterator, label_patterns: list[str]) -> tuple[str, object]: """Read a single field matching one of the given label_patterns. Parameters ---------- lit The line iterator to read the data from. label_patterns A list of Unix shell-style wildcard patterns. The next field matching one of the patterns is returned Returns ------- label The name of the field value The scalar or array data of the field. """ while True: # find a sane header line line = next(lit) label = line[:43].strip() words = line[43:].split() if not words: continue if words[0] == "I": datatype = int elif words[0] == "R": datatype = float else: continue if not ( label_patterns is None or any(fnmatch(label, label_pattern) for label_pattern in label_patterns) ): continue if len(words) == 2: try: return label, datatype(words[1]) except ValueError as exc: raise LoadError(f"Could not interpret as {datatype}: {words[1]}", lit) from exc elif len(words) == 3: if words[1] != "N=": raise LoadError("Expected N= not found.", lit) length = int(words[2]) value = np.zeros(length, datatype) counter = 0 words = [] while counter < length: if not words: words = next(lit).split() word = words.pop(0) try: value[counter] = datatype(word) except (ValueError, OverflowError) as exc: raise LoadError(f"Could not interpret as {datatype}: {word}", lit) from exc counter += 1 return label, value def _load_dm(label: str, fchk: dict, result: dict, key: str): """Load a density matrix from the FCHK file if present. Parameters ---------- label The label in the FCHK file. fchk The dictionary with labels from the FCHK file. result The output dictionary. key: The key to be used in the output dictionary. """ if label in fchk: result[key] = _triangle_to_dense(fchk[label]) def _triangle_to_dense(triangle: NDArray[float]) -> NDArray[float]: """Convert a symmetric matrix in triangular storage to a dense square matrix. Parameters ---------- triangle A row vector containing all the unique matrix elements of symmetric matrix. (Either the lower-triangular part in row major-order or the upper-triangular part in column-major order.) Returns ------- A square symmetric matrix. """ nrow = int(np.round((np.sqrt(1 + 8 * len(triangle)) - 1) / 2)) result = np.zeros((nrow, nrow)) begin = 0 for irow in range(nrow): end = begin + irow + 1 result[irow, : irow + 1] = triangle[begin:end] result[: irow + 1, irow] = triangle[begin:end] begin = end return result # The fchk file has a very rigid format, to dump the information are # theses functions, both scalars and arrays, integer and real(float) variables def _dump_integer_scalars(name: str, val: int, f: TextIO): """Dumper for a scalar integer.""" print(f"{name:40} I {int(val):12d}", file=f) def _dump_real_scalars(name: str, val: float, f: TextIO): """Dumper for a scalar float.""" print(f"{name:40} R {float(val): 16.8E}", file=f) def _dump_integer_arrays(name: str, val: NDArray[int], f: TextIO): """Dumper for a array of integers.""" nval = val.size if nval != 0: np.reshape(val, nval) print(f"{name:40} I N={nval:12}", file=f) k = 0 for i in range(nval): print(f"{int(val[i]):12}", file=f, end="") k += 1 if k == 6 or i == nval - 1: print("", file=f) k = 0 def _dump_real_arrays(name: str, val: NDArray[float], f: TextIO): """Dumper for a array of float.""" nval = val.size if nval != 0: np.reshape(val, nval) print(f"{name:40} R N={nval:12}", file=f) k = 0 for i in range(nval): print(f"{val[i]: 16.8E}", file=f, end="") k += 1 if k == 5 or i == nval - 1: print("", file=f) k = 0
[docs] def prepare_dump(filename: str, data: IOData): """Check the compatibility of the IOData object with the FCHK format. Parameters ---------- filename The file to be written to, only used for error messages. data The IOData instance to be checked. """ if data.mo is not None: if data.mo.kind == "generalized": raise PrepareDumpError("Cannot write FCHK file with generalized orbitals.", filename) na = int(np.round(np.sum(data.mo.occsa))) if not ((data.mo.occsa[:na] == 1.0).all() and (data.mo.occsa[na:] == 0.0).all()): raise PrepareDumpError( "Cannot dump FCHK because it does not have fully occupied alpha orbitals " "followed by fully virtual ones.", filename, ) nb = int(np.round(np.sum(data.mo.occsb))) if not ((data.mo.occsb[:nb] == 1.0).all() and (data.mo.occsb[nb:] == 0.0).all()): raise PrepareDumpError( "Cannot dump FCHK because it does not have fully occupied beta orbitals " "followed by fully virtual ones.", filename, )
[docs] @document_dump_one( "Gaussian Formatted Checkpoint", ["atnums", "atcorenums"], [ "atcharges", "atcoords", "atfrozen", "atgradient", "athessian", "atmasses", "charge", "energy", "lot", "mo", "one_rdms", "obasis_name", "extra", "moments", ], ) def dump_one(f: TextIO, data: IOData): """Do not edit this docstring. It will be overwritten.""" # write title print("{:72}".format(data.title or "FCHK generated by IOData"), file=f) # write run type, level of theory, and basis set name (all in uppercase) items = [getattr(data, item) or "NA" for item in ["run_type", "lot", "obasis_name"]] if items[0] == "energy": items[0] = "SP" print(f"{items[0].upper():10s}{items[1].upper():30s}{items[2].upper():>33s}", file=f) # write basic information _dump_integer_scalars("Number of atoms", data.natom, f) _dump_integer_scalars("Number of electrons", int(data.nelec), f) if data.charge is not None: _dump_integer_scalars("Charge", int(data.charge), f) if data.mo is not None: na = int(np.round(np.sum(data.mo.occsa))) nb = int(np.round(np.sum(data.mo.occsb))) # assign number of alpha and beta electrons multiplicity = abs(na - nb) + 1 _dump_integer_scalars("Multiplicity", multiplicity, f) _dump_integer_scalars("Number of alpha electrons", na, f) _dump_integer_scalars("Number of beta electrons", nb, f) # write atomic numbers, nuclear charges, and atomic coordinates _dump_integer_arrays("Atomic numbers", data.atnums, f) _dump_real_arrays("Nuclear charges", data.atcorenums, f) if data.atcoords is not None: _dump_real_arrays("Current cartesian coordinates", data.atcoords.flatten(), f) # write atomic weights if data.atmasses is not None: masses = data.atmasses / amu _dump_integer_arrays("Integer atomic weights", masses.round(), f) _dump_real_arrays("Real atomic weights", masses, f) # write molecular orbital basis set if data.obasis is not None: # number of primitives per shell nprims = np.array([shell.nprim for shell in data.obasis.shells]) exponents = np.array([item for shell in data.obasis.shells for item in shell.exponents]) coeffs = np.array([s.coeffs[i][0] for s in data.obasis.shells for i in range(s.nprim)]) coordinates = np.array([data.atcoords[shell.icenter] for shell in data.obasis.shells]) shell_to_atom = np.array([shell.icenter + 1 for shell in data.obasis.shells]) # get list of shell types: 0=s, 1=p, -1=sp, 2=6d, -2=5d, 3=10f, -3=7f... shell_types = [] for shell in data.obasis.shells: if shell.ncon == 1 and shell.kinds == ["c"]: shell_types.append(shell.angmoms[0]) elif shell.ncon == 1 and shell.kinds == ["p"]: shell_types.append(-1 * shell.angmoms[0]) elif shell.ncon == 2 and shell.angmoms == [0, 1]: shell_types.append(-1) else: raise DumpError("Cannot identify type of shell!", f) num_pure_d_shells = sum([1 for st in shell_types if st == 2]) num_pure_f_shells = sum([1 for st in shell_types if st == 3]) _dump_integer_scalars("Number of basis functions", data.obasis.nbasis, f) _dump_integer_scalars("Number of independent functions", data.obasis.nbasis, f) _dump_integer_scalars("Number of contracted shells", len(data.obasis.shells), f) _dump_integer_scalars("Number of primitive shells", nprims.sum(), f) _dump_integer_scalars("Pure/Cartesian d shells", num_pure_d_shells, f) _dump_integer_scalars("Pure/Cartesian f shells", num_pure_f_shells, f) _dump_integer_scalars("Highest angular momentum", np.amax(np.abs(shell_types)), f) _dump_integer_scalars("Largest degree of contraction", np.amax(nprims), f) _dump_integer_arrays("Shell types", np.array(shell_types), f) _dump_integer_arrays("Number of primitives per shell", nprims, f) _dump_integer_arrays("Shell to atom map", shell_to_atom, f) _dump_real_arrays("Primitive exponents", exponents, f) _dump_real_arrays("Contraction coefficients", coeffs, f) if -1 in shell_types: sp_coeffs = [] for shell, shell_type in zip(data.obasis.shells, shell_types): if shell_type == -1: sp_coeffs.extend([shell.coeffs[i][1] for i in range(shell.nprim)]) else: sp_coeffs.extend([0.0] * shell.nprim) _dump_real_arrays("P(S=P) Contraction coefficients", np.array(sp_coeffs), f) _dump_real_arrays("Coordinates of each shell", coordinates.flatten(), f) # write energy if data.energy is not None: _dump_real_scalars("SCF Energy", data.energy, f) _dump_real_scalars("Total Energy", data.energy, f) # write MO energies & coefficients if data.mo is not None: # convert to FCHK basis conventions permutation, signs = convert_conventions(data.obasis, CONVENTIONS) coeffsa = data.mo.coeffsa[permutation] * signs.reshape(-1, 1) _dump_real_arrays("Alpha Orbital Energies", data.mo.energiesa, f) _dump_real_arrays("Alpha MO coefficients", coeffsa.transpose().flatten(), f) if data.mo.kind == "unrestricted": coeffsb = data.mo.coeffsb[permutation] * signs.reshape(-1, 1) _dump_real_arrays("Beta Orbital Energies", data.mo.energiesb, f) _dump_real_arrays("Beta MO coefficients", coeffsb.transpose().flatten(), f) # write reduced density matrix, if available # get level of theory, use 'NA' if not available level = data.lot.upper() if data.lot is not None else "NA" for item in ["MP2", "MP3", "CC", "CI"]: if item in level: level = item for key, arr in data.one_rdms.items(): # get lower triangular elements of RDM mat = arr[np.tril_indices(arr.shape[0])] # identify type of RDMs if key == "scf": title = "Total SCF Density" elif key == "scf_spin": title = "Spin SCF Density" elif key == "post_scf_ao": title = f"Total {level} Density" elif key == "post_scf_spin_ao": title = f"Spin {level} Density" else: title = "Total SCF Density" _dump_real_arrays(title, mat, f) # write atomic charges if "mulliken" in data.atcharges: _dump_real_arrays("Mulliken Charges", data.atcharges["mulliken"], f) if "esp" in data.atcharges: _dump_real_arrays("ESP Charges", data.atcharges["esp"], f) if "npa" in data.atcharges: _dump_real_arrays("NPA Charges", data.atcharges["npa"], f) if "mbs" in data.atcharges: _dump_real_arrays("MBS Charges", data.atcharges["mbs"], f) if "hirshfeld" in data.atcharges: _dump_real_arrays("Type 6 Charges", data.atcharges["hirshfeld"], f) if "cm5" in data.atcharges: _dump_real_arrays("Type 7 Charges", data.atcharges["cm5"], f) # write atomic gradient if data.atgradient is not None: _dump_real_arrays("Cartesian Gradient", data.atgradient.flatten(), f) # write atomic hessian if data.athessian is not None: arr = data.athessian[np.tril_indices(data.athessian.shape[0])] _dump_real_arrays("Cartesian Force Constants", arr, f) # write moments if (1, "c") in data.moments: _dump_real_arrays("Dipole Moment", data.moments[(1, "c")], f) if (2, "c") in data.moments and len(data.moments[(2, "c")]) != 0: # quadrupole moments are stored as XX, XY, XZ, YY, YZ, ZZ in IOData, so they need to # be permuted to have XX, YY, ZZ, XY, XZ, YZ order for FCHK. quadrupole = data.moments[(2, "c")][[0, 3, 5, 1, 2, 4]] _dump_real_arrays("Quadrupole Moment", quadrupole, f) # write polarizability tensor if "polarizability_tensor" in data.extra: arr = data.extra["polarizability_tensor"] arr = arr[np.tril_indices(arr.shape[0])] _dump_real_arrays("Polarizability", arr, f)