Energy Levels of Er3+ and Pr3+ in Hexagonal LaBr3

Abstract

The spectra of Er3+ in LaBr3 are similar to, but not the same as, those of Er3+ in LaCl3. The Stark splittings of the Y and Z groups are used to determine the crystalline-field parameters for LaBr3, which are B20=117, B40=−39.6, B60=−19.2, and B66=212 cm−1. These are significantly different from those of LaCl3. The centers of gravity of the excited Stark groups are higher in LaCl3 than in LaBr3, and this shift increases with increasing wavenumber. Spectra and energy levels of Pr3+ in LaBr3 are also given.