# A program for computing magnetic dipole and electric quadrupole hyperfine constants from MCHF wavefunctions

## Description

Abstract Given an electronic wave function, generated by the MCHF program (LS format) or the MCHF_CI program (LSJ format), this program computes the hyperfine interaction constants, A_Jand B_J . In strong experimental magnetic fields, the splitting is also affected by the off-diagonal hyperfine constants A_(J,J-1), B_(J,J-1), and B_(J,J-2)and these are computed as well, depending on the input data. Title of program: MCHF_HFS Catalogue Id: ACLE_v1_0 Nature of problem The atomic hyperfine splitting is determined by the hyperfine interaction constants AJ and BJ [1]. In strong external magnetic fields, where J is no longer a good quantum number, the splitting is also affected by the off-diagonal hyperfine constants AJ,J-1, BJ,J-1 and BJ,J-2 [2,3,4]. This program calculates the hyperfine constants using an electronic wavefunction generated with the MCHF or MCHF_CI programs of Froese Fischer [5]. Versions of this program held in the CPC repository in Mendeley Data ACLE_v1_0; MCHF_HFS; 10.1016/0010-4655(93)90022-5 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)