iodata.orbitals module¶

Data structure for molecular orbitals.

class MolecularOrbitals(kind, norba, norbb, occs=None, coeffs=None, energies=None, irreps=None)[source]¶

Bases: object

Class of Orthonormal Molecular Orbitals.

kind¶: Type of molecular orbitals, which can be ‘restricted’, ‘unrestricted’, or ‘generalized’.

norba¶: Number of (occupied and virtual) alpha molecular orbitals. Set to None in case oftype==’generalized’.

norbb¶: Number of (occupied and virtual) beta molecular orbitals. Set to None in case of type==’generalized’. This is expected to be equal to norba for the restricted kind.

occs¶: Molecular orbital occupation numbers. The length equals the number of columns of coeffs.

coeffs¶: Molecular orbital coefficients. In case of restricted: shape = (nbasis, norba) = (nbasis, norbb). In case of unrestricted: shape = (nbasis, norba + norbb). In case of generalized: shape = (2 * nbasis, norb), where norb is the total number of orbitals.

energies¶: Molecular orbital energies. The length equals the number of columns of coeffs.

irreps¶: Irreducible representation. The length equals the number of columns of coeffs.

Warning¶

Type:: the interpretation of the occupation numbers may only be suitable

for single-reference orbitals (not fractionally occupied natural orbitals.)

When an occupation number is in ]0, 1], it is assumed that an alpha orbital

is (fractionally) occupied. When an occupation number is in ]1, 2], it is

assumed that the alpha orbital is fully occupied and the beta orbital is

(fractionally) occupied.

__init__(kind, norba, norbb, occs=None, coeffs=None, energies=None, irreps=None)¶: Method generated by attrs for class MolecularOrbitals.

coeffs: ndarray¶

property coeffsa¶: Return alpha orbital coefficients.

property coeffsb¶: Return beta orbital coefficients.

energies: ndarray¶

property energiesa¶: Return alpha orbital energies.

property energiesb¶: Return beta orbital energies.

irreps: ndarray¶

property irrepsa¶: Return alpha irreps.

property irrepsb¶: Return beta irreps.

kind: str¶

property nbasis¶: Return the number of spatial basis functions.

property nelec: float¶: Return the total number of electrons.

property norb¶

Return the number of spatially distinct orbitals.

Notes

In case of restricted wavefunctions, this may be less than just the sum of norba and norbb, because alpha and beta orbitals share the same spatical dependence.

norba: int¶

norbb: int¶

occs: ndarray¶

property occsa¶: Return alpha occupation numbers.

property occsb¶: Return beta occupation numbers.

property spinpol: float¶: Return the spin polarization of the Slater determinant.

validate_norbab(mo, attribute, value)[source]¶

Validate the norba or norbb value assigned to a MolecularOrbitals object.

Parameters:

mo – The MolecularOrbitals instance.
attribute – Attribute instancce being changed.
value – The new value.