Accession Number : AD0664769

Title :   COMPARISON OF THE GROUND TERM ENERGY LEVELS AND CRYSTAL FIELD PARAMETERS OF TERBIUM IN SCHEELITE CRYSTALS,

Corporate Author : HARRY DIAMOND LABS WASHINGTON D C

Personal Author(s) : Stephens,R. R. ; Wortman,D. E.

Report Date : NOV 1967

Pagination or Media Count : 24

Abstract : A study was made of the infrared absorption spectra of triply ionized terbium in single crystals of CaWO4, SrWO4, CaMoO4, and SrMoO4. Particular emphasis was placed on determining the crystal field parameters for these host crystals of the scheelite structure. In recording the data, the crystals were held at temperatures near that of liquid helium (4.2K) or of liquid nitrogen (77K). The transitions observed were from the (7)F6 ground multiplet to the (7)F0, (7)F1, (7)F2, and (7)F3 multiplets. Russell-Saunders wave functions were used in the calculations. The spin-orbit and crystal field interactions were considered responsible for the splitting of the energy levels of the (7)F ground term. The S4 symmetry properties of the crystalline field were used to simplify the analysis of the spectra and the IBM7094 computer calculations. The magnitude of the leading terms in the crystal field potential expansion were found to be greater for the Ca lattices than for the Sr lattices. Also the Tb(3+) spectra in the Sr lattices have fewer extra lines, as predicted by the symmetry properties, than in the Ca lattices. The theoretically predicted energy levels for the entire ground term of triply ionized terbium in each scheelite are given as are the experimental energy levels determined from the recorded spectra. (Author)

Descriptors :   (*CRYSTAL DEFECTS, ATOMIC ENERGY LEVELS), (*TERBIUM, *ATOMIC ENERGY LEVELS), (*INFRARED SPECTROSCOPY, TERBIUM), SINGLE CRYSTALS, CALCIUM COMPOUNDS, STRONTIUM COMPOUNDS, TUNGSTATES, MOLYBDATES, ABSORPTION SPECTRA, ELECTRON TRANSITIONS, LASERS, MATERIALS, GROUND STATE

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE