MATRIX ISOLATED LUMINESCENCE SPECTROSCOPY OF URANIUM HEXAFLUORIDE

Abstract

Luminescence spectra are presented for $UF_{6}$ in thin films $(11-120^\circ K$) and a variety of inert gas matrices $(11-40^\circ K$ ). In the region 4050-4700 {\AA} more than 150 lines are observed (in an argon matrix at a 1:200 $UF_{6}$/Ar ratio). Assignments of the vibrational structure, site splittings, and the nature of the emitting state are presented. Variations in the 0-0 intensity from Ar matrices to thin films supports proposed changes in structure from 0$_{h}$ in the matrix to $D_{4h}$ in the thin film. The influence of matrix gas, $UF_{6}$ /matrix gas ratio, and temperature on the structure of the spectrum and on the position of the 0-0 band is discussed. Possible mechanisms for spectral broadening with temperature and $UF_{6}$ concentration are presented together with appropriate lifetime data. Corrected high resolution excitation spectra are presented and discussed in terms of their relationships to the absorption spectrum.