integral_conversion

Module for converting integrals to fermionic format.

funcintegrals_to_fermion(h0, h1, h2) -> FermiOperator

Convert molecular integrals into a fermionic Hamiltonian.

integrals should describe an unrestricted molecular Hamiltonian in a spatial-orbital basis.

paramh0float

is the scalar (core) energy containing the nuclear repulsion energy and any frozen-core or inactive-space contributions.

paramh1ndarray

is an array of shape (2, n_orb, n_orb) containing the alpha- and beta-spin one-electron integrals, corresponding to the kinetic-energy operator and electron-nucleus attraction operator (plus any effective one-electron contributions from frozen orbitals or inactive electrons).

paramh2ndarray

is an array of shape (3, n_orb, n_orb, n_orb, n_orb) containing the alpha-alpha, beta-beta, and alpha-beta electron-repulsion integrals in chemist's notation, $(pq|rs)=\int \phi_p(r_1)\phi_q(r_1) r_{12}^{-1}\phi_r(r_2)\phi_s(r_2)\mathrm{d}r_1\mathrm{d}r_2$

Returns

monoprop.fermi.FermiOperator

Hamiltonian in FermiOperator format.