qiskit.chemistry.QMolecule

class QMolecule(filename=None)

Molecule data class containing driver result.

When one of the chemistry drivers is run and instance of this class is returned. This contains various properties that are made available in a consistent manner across the various drivers.

Note that values here, for the same input molecule to each driver, may be vary across the drivers underlying code implementation. Also some drivers may not provide certain fields such as dipole integrals in the case of PyQuanteDriver.

This class provides methods to save it and load it again from an HDF5 file

__init__(filename=None)

Initialize self. See help(type(self)) for accurate signature.

Methods

Z(natom)
__init__([filename])	Initialize self.
has_dipole_integrals()	Check if dipole integrals are present.
load()	loads info saved.
log()	log properties
onee_to_spin(mohij[, mohij_b, threshold])	Convert one-body MO integrals to spin orbital basis
oneeints2mo(ints, moc)	Converts one-body integrals from AO to MO basis
remove_file([file_name])	remove file
save([file_name])	Saves the info from the driver.
twoe_to_spin(mohijkl[, mohijkl_bb, …])	Convert two-body MO integrals to spin orbital basis
twoeints2mo(ints, moc)	Converts two-body integrals from AO to MO basis
twoeints2mo_general(ints, moc1, moc2, moc3, moc4)

Attributes

BOHR
DEBYE
QMOLECULE_VERSION
core_orbitals	Returns: A list of core orbital indices.
filename	returns temp file path
one_body_integrals	Returns one body electron integrals.
symbols
two_body_integrals	Returns two body electron integrals.
x_dipole_integrals	returns x_dipole_integrals
y_dipole_integrals	returns y_dipole_integrals
z_dipole_integrals	returns z_dipole_integrals

Z(natom)

property core_orbitals

Returns: A list of core orbital indices.

Return type

List[int]

property filename

returns temp file path

has_dipole_integrals()

Check if dipole integrals are present.

load()

loads info saved.

log()

log properties

property one_body_integrals

Returns one body electron integrals.

static onee_to_spin(mohij, mohij_b=None, threshold=1e-12)

Convert one-body MO integrals to spin orbital basis

Takes one body integrals in molecular orbital basis and returns integrals in spin orbitals ready for use as coefficients to one body terms 2nd quantized Hamiltonian.

Parameters

• mohij (numpy.ndarray) – One body orbitals in molecular basis (Alpha)

• mohij_b (numpy.ndarray) – One body orbitals in molecular basis (Beta)

• threshold (float) – Threshold value for assignments

Returns

One body integrals in spin orbitals

Return type

numpy.ndarray

static oneeints2mo(ints, moc)

Converts one-body integrals from AO to MO basis

Returns one electron integrals in AO basis converted to given MO basis

Parameters

• ints (numpy.ndarray) – N^2 one electron integrals in AO basis

• moc (numpy.ndarray) – Molecular orbital coefficients

Returns

integrals in MO basis

Return type

numpy.ndarray

remove_file(file_name=None)

remove file

save(file_name=None)

Saves the info from the driver.

property two_body_integrals

Returns two body electron integrals.

static twoe_to_spin(mohijkl, mohijkl_bb=None, mohijkl_ba=None, threshold=1e-12)

Convert two-body MO integrals to spin orbital basis

Takes two body integrals in molecular orbital basis and returns integrals in spin orbitals ready for use as coefficients to two body terms in 2nd quantized Hamiltonian.

Parameters

• mohijkl (numpy.ndarray) – Two body orbitals in molecular basis (AlphaAlpha)

• mohijkl_bb (numpy.ndarray) – Two body orbitals in molecular basis (BetaBeta)

• mohijkl_ba (numpy.ndarray) – Two body orbitals in molecular basis (BetaAlpha)

• threshold (float) – Threshold value for assignments

Returns

Two body integrals in spin orbitals

Return type

numpy.ndarray

static twoeints2mo(ints, moc)

Converts two-body integrals from AO to MO basis

Returns two electron integrals in AO basis converted to given MO basis

Parameters

• ints (numpy.ndarray) – N^2 two electron integrals in AO basis

• moc (numpy.ndarray) – Molecular orbital coefficients

Returns

integrals in MO basis

Return type

numpy.ndarray

static twoeints2mo_general(ints, moc1, moc2, moc3, moc4)

property x_dipole_integrals

returns x_dipole_integrals

property y_dipole_integrals

returns y_dipole_integrals

property z_dipole_integrals

returns z_dipole_integrals