# A general program for computing angular integrals of the Breit-Pauli Hamiltonian

## Description

Abstract The MCHF_BREIT program performs the angular integrations necessary for expressing the matrix elements of the Breit-Pauli Hamiltonian (except for the orbit-orbit operator) as linear combinations of radial integrals. All matrix elements for a given list of configuration states may be evaluated or selected subsets. An orthonormal set of orbitals is assumed. Title of program: MCHF_BREIT Catalogue Id: ABZY_v1_0 Nature of problem In the Breit-Pauli LSJ approximation, the wave function is expanded in terms of configuration state functions with differing LS term values. To determine the coefficients in the expansion, the interaction matrix elements need to be expressed in terms of sums of radial integrals. This program calculates the coefficients of these integrals and produces a file INT.LST appropriate for input to the MCHF_CI program. Versions of this program held in the CPC repository in Mendeley Data ABZY_v1_0; MCHF_BREIT; 10.1016/0010-4655(91)90138-B This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)