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

Given electronic wave functions generated by the grasp2K relativistic atomic structure package, this program calculates diagonal magnetic dipole image and electric quadrupole image hyperfine interaction constants and Landé image 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.