RAMAN SPECTRUM OF LABR3

The first-order raman spectrum of LaBr3 is examined. All of the six raman-active vibrations are observed and the C6h point-group symmetry assignments for the lines are given: 83 cm-1, E2g; 116 cm-1, Ag; 122 cm-1, E1g; 137.6 cm-1, Ag; 139.2 cm-1, E2g; 146 cm-1, E2g. The lines at 137.6 cm-1 and 139.2 cm-1 are found to be resolvable at 77°K but not at temperatures above 180°K. The Raman spectrum of LaBr3 is compared with that of the isomorphic LaCl3, which exhibits only five of the six Raman-active lines. © 1968 The American Physical Society.