Energy levels, densities of states, electronic densities, electrostatic interaction integral parameters Fk and spin-orbit coupling parameters ζ4f for ZnS: Tm3+ are calculated self-consistently, using both one-electron local density discrete variational non-relativistic Hartree-Fock-Slater (HFS) and relativistic Dirac-Slater (DS) cluster models. In these calculations, both spin-restricted and spin-polarized models are considered. The finite clusters calculated include TmS4 and TmS4Zn12 clusters for cubic ZnS, which are embedded in the crystal environment. The spin-orbit coupling parameter ζ4f derived from DS cluster calculations is equal to 2689 cm-1, rather near the result of the relativistic Hartree-Fock free ion model. The parameters Fk and ζ4f are further calculated from the 4f radial wave function obtained by solving the HFS and the DS atomic equations. It is shown that by decreasing the effective exchange-correlation potential, these parameters can be reduced to approximately match empirical values. A comparison of the excited energy level scheme of ZnS:Tm derived from the calculated parameters and the experimental spectra is presented.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics