Investigations of 4f5d Transitions of Ce+3 in CaF2

Abstract
The 4f5d transitions of Ce+3 in CaF2 crystals are investigated, using thermoluminescence and other optical techniques. the effect of heat treatment on the thermoluminescence, luminescence, and absorption spectra is shown. The differences in spectra between as-received and heat-treated specimens arise from the variation in abundance of rare-earth ion sites of various point symmetries. This variation is caused by oxygen diffusing into the crystals during heat treatment. On cooling to liquid-nitrogen temperature, structure develops on most of these spectra. This structure is discussed and a tentative explanation is suggested.