Spin-averaged Hartree-Fock procedure for spectroscopic calculations: The absorption spectrum of Mn2+ in ZnS crystals

A spin-averaged Hartree–Fock (SAHF) procedure is examined within the framework of the configuration-averaged methodology proposed earlier. The SAHF method produces reasonable total energies and can be successfully used for the calculation of electronic spectra, especially in the cases of marked energy separation between the spin states. An example is given with the spectroscopy of Mn2+ ions in the ZnS crystal where the SAHF procedure provides a more accurate interpretation of the electronic spectrum than that obtained by other self-consistent-field methods.