HFSZEEMAN—A program for computing weak and intermediate field fine and hyperfine structure Zeeman splittings from MCDHF wave functions

Given electronic wave functions generated by the grasp2K relativistic atomic structure package, this program calculates diagonal magnetic dipole AJAJ and electric quadrupole BJBJ hyperfine interaction constants and Landé gJgJ factors. In addition the program computes diagonal and off-diagonal reduced hyperfine and Zeeman matrix elements and constructs the total interaction matrix for an atom in an external magnetic field. By diagonalizing the interaction matrix and plotting eigenvalues as functions of the magnetic field, Zeeman splittings of hyperfine levels are obtained. The method is applicable in the weak and intermediate field regions and yields results that are useful when analyzing spectra from e.g. EBIT sources and magnetic stars. The program can also be used in the field free limit to calculate mixing coefficients that determine rates of hyperfine induced transitions. For atoms with zero nuclear spin I the program computes splittings of the fine-structure levels.Program summaryProgram title: HFSZEEMANCatalogue identifier: ADZS_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZS_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 1528No. of bytes in distributed program, including test data, etc.: 294 664Distribution format: tar.gzProgramming language:Fortran, MatlabComputer: IBM-compatible PC, unix workstationOperating system: Unix, LinuxClassification: 11.6Subprograms used: Cat Id: ADZL_v1_0;   Title: grasp2K v1.0;  Reference: CPC 177 (2007) 597Nature of problem: Prediction of weak and intermediate field Zeeman splittings of fine- and hyperfine structure levels using multiconfiguration Dirac–Hartree–Fock wave functions.Solution method: The electronic wave function for a state labeled ΓJM is expanded in terms of jj  -coupled configuration state functions |ΓJM〉=∑γcγ|γJM〉|ΓJM〉=∑γcγ|γJM〉. In this representation the reduced matrix elements used to construct the interaction matrix can be computed as sums over one-particle radial integrals. By diagonalizing the interaction matrix and plotting eigenvalue as functions of the magnetic field, Zeeman splittings of fine- and hyperfine structure levels are obtained.Restrictions: The complexity of the cases that can be handled is entirely determined by the grasp2K package [P. Jönsson, H. Xe, C. Froese Fischer, I.P. Grant, Comput. Phys. Commun. 177 (2007) 597] used for the generation of the electronic wave functions.Running time: CPU time required to execute test cases: a few seconds.