Absorption Spectra of the Samarium Ion in Solids. III. Absorption of Sm(BrO3)3 and a Partial Energy-Level Diagram for the Sm+++ Ion as It Exists in Crystalline Sm(BrO3)3·9H2O

Abstract

The absorption spectrum of ${\mathrm{S}\mathrm{m}\left(\mathrm{B}\mathrm{r}{\mathrm{O}}_3\right)}_3$ ·9${\mathrm{H}}_2$O has been studied at four temperatures between 20° and 298°K. The temperature variation in the absorption intensities is used to determine the location of excited lower levels situated at 39 and 68 ${\mathrm{cm}}^{-1\mathrm{}}$ above the basic one. Other levels from 100 to 230 ${\mathrm{cm}}^{-1\mathrm{}}$ above the normal state are probable. Between 78° and 20° many lines show a marked change, becoming double at the lower temperature. This is shown to be compatible with a splitting of the levels into new ones at 0, 37, 45, 67 and 82 ${\mathrm{cm}}^{-1\mathrm{}}$. Selection rules are indicated which show two apparently independent sets of these levels; 0, 37, 82 and one group of high levels; and 0, 45, 67 and another group of upper levels. This low-temperature splitting may be due either (1) to actual removal of degeneracy or (2) to development of two types of ${\mathrm{Sm}}^{+++}$ ion, differing in crystal environments. Either effect could presumably be caused by small changes in the crystal dimensions and symmetry. The hexagonal bromate shows less extension and complexity of upper multiplets and the excited lower levels are closer to the basic one than in the less symmetrical monoclinic chloride previously studied.