ffsim.MolecularData¶

class ffsim.MolecularData(*, core_energy, one_body_integrals, two_body_integrals, norb, nelec, atom=None, basis=None, spin=None, symmetry=None, mo_coeff=None, mo_occ=None, active_space=None, hf_energy=None, hf_mo_coeff=None, hf_mo_occ=None, mp2_energy=None, mp2_t2=None, ccsd_energy=None, ccsd_t1=None, ccsd_t2=None, cisd_energy=None, cisd_vec=None, sci_energy=None, sci_vec=None, fci_energy=None, fci_vec=None, dmrg_energy=None, dipole_integrals=None, orbital_symmetries=None)[source]¶

Bases: object

Class for storing molecular data.

core_energy¶

The core energy.

Type:: float

one_body_integrals¶

The one-body integrals.

Type:: np.ndarray

two_body_integrals¶

The two-body integrals in compressed format.

Type:: np.ndarray

norb¶

The number of spatial orbitals.

Type:: int

nelec¶

The number of alpha and beta electrons.

Type:: tuple[int, int]

atom¶

The coordinates of the atoms in the molecule.

Type:: list[tuple[str, list[float]]] | None

basis¶

The basis set, e.g. “sto-6g”.

Type:: str | None

spin¶

The spin of the molecule.

Type:: int | None

symmetry¶

The symmetry of the molecule.

Type:: str | None

mo_coeff¶

Molecular orbital coefficients in the AO basis.

Type:: np.ndarray | None

mo_occ¶

Molecular orbital occupancies.

Type:: np.ndarray | None

active_space¶

The molecular orbitals included in the active space.

Type:: list[int] | None

hf_energy¶

The Hartree-Fock energy.

Type:: float | None

hf_mo_coeff¶

Hartree-Fock canonical orbital coefficients in the AO basis.

Type:: np.ndarray | None

hf_mo_occ¶

Hartree-Fock canonical orbital occupancies.

Type:: np.ndarray | None

mp2_energy¶

The MP2 energy.

Type:: float | None

mp2_t2¶

The MP2 t2 amplitudes.

Type:: np.ndarray | tuple[np.ndarray, np.ndarray, np.ndarray] | None

ccsd_energy¶

The CCSD energy.

Type:: float | None

ccsd_t1¶

The CCSD t1 amplitudes.

Type:: np.ndarray | tuple[np.ndarray, np.ndarray] | None

ccsd_t2¶

The CCSD t2 amplitudes.

Type:: np.ndarray | tuple[np.ndarray, np.ndarray, np.ndarray] | None

cisd_energy¶

The CISD energy.

Type:: float | None

cisd_vec¶

The CISD state vector.

Type:: np.ndarray | None

sci_energy¶

The SCI energy.

Type:: float | None

sci_vec¶

The SCI state vector coefficients, spin alpha strings, and spin beta strings.

Type:: tuple[np.ndarray, np.ndarray, np.ndarray] | None

fci_energy¶

The FCI energy.

Type:: float | None

fci_vec¶

The FCI state vector.

Type:: np.ndarray | None

dipole_integrals¶

The dipole integrals.

Type:: np.ndarray | None

orbital_symmetries¶

The orbital symmetries.

Type:: list[str] | None

Methods

`from_fcidump`(file)	Initialize a MolecularData from an FCIDUMP file.
`from_json`(file[, compression])	Load a MolecularData from a (possibly compressed) JSON file.
`from_scf`(hartree_fock[, active_space])	Initialize a MolecularData object from a Hartree-Fock calculation.
`run_ccsd`([t1, t2, store_t1, store_t2])	Run CCSD and store results.
`run_cisd`(*[, store_cisd_vec])	Run CISD and store results.
`run_fci`(*[, store_fci_vec])	Run FCI and store results.
`run_mp2`(*[, store_t2])	Run MP2 and store results.
`run_sci`(*[, store_sci_vec])	Run SCI and store results.
`to_fcidump`(file)	Save data to disk in FCIDUMP format.
`to_json`(file[, compression])	Serialize to JSON format, optionally compressed, and save to disk.

static from_fcidump(file)[source]¶

Initialize a MolecularData from an FCIDUMP file.

Parameters:: file (str | bytes | PathLike) – The FCIDUMP file path.
Return type:: MolecularData

static from_json(file, compression=None)[source]¶

Load a MolecularData from a (possibly compressed) JSON file.

Parameters:

file (str | bytes | PathLike) – The file path to read from.
compression (str | None) – The compression algorithm, if any, which was used to compress the file. Options: "gzip", "bz2", "lzma".

Return type:

MolecularData

Returns: The MolecularData object.

static from_scf(hartree_fock, active_space=None)[source]¶

Initialize a MolecularData object from a Hartree-Fock calculation.

Parameters:

hartree_fock (SCF) – The Hartree-Fock object.
active_space (Iterable[int] | None) – An optional list of orbitals to use for the active space.

Return type:

MolecularData

run_ccsd(t1=None, t2=None, *, store_t1=False, store_t2=False)[source]¶

Run CCSD and store results.

Return type:: None

run_cisd(*, store_cisd_vec=False)[source]¶

Run CISD and store results.

Return type:: None

run_fci(*, store_fci_vec=False)[source]¶

Run FCI and store results.

Return type:: None

run_mp2(*, store_t2=False)[source]¶: Run MP2 and store results.

run_sci(*, store_sci_vec=False)[source]¶

Run SCI and store results.

Return type:: None

to_fcidump(file)[source]¶

Save data to disk in FCIDUMP format.

Note

The FCIDUMP format does not retain all information stored in the MolecularData object. To serialize a MolecularData object losslessly, use the to_json() method to save to JSON format.

Parameters:: file (str | bytes | PathLike) – The file path to save to.
Return type:: None

to_json(file, compression=None)[source]¶

Serialize to JSON format, optionally compressed, and save to disk.

Parameters:

file (str | bytes | PathLike) – The file path to save to.
compression (str | None) – The optional compression algorithm to use. Options: "gzip", "bz2", "lzma".

Return type:

None

Attributes

`active_space`
`atom`
`basis`
`ccsd_energy`
`ccsd_t1`
`ccsd_t2`
`cisd_energy`
`cisd_vec`
`dipole_integrals`
`dmrg_energy`
`fci_energy`
`fci_vec`
`hamiltonian`	The Hamiltonian defined by the molecular data.
`hf_energy`
`hf_mo_coeff`
`hf_mo_occ`
`mo_coeff`
`mo_occ`
`mole`	The PySCF Mole class for this molecular data.
`mp2_energy`
`mp2_t2`
`orbital_symmetries`
`scf`	A PySCF SCF class for this molecular data.
`sci_energy`
`sci_vec`
`spin`
`symmetry`
`core_energy`
`one_body_integrals`
`two_body_integrals`
`norb`
`nelec`