Raman Scattering in Wurtzite-Type AgI Crystals

Abstract

The polarized laser-Raman scattering of oriented single crystals of β-AgI has been investigated at 300°, 80°, and 4.2°K. The fundamental optic lattice modes predicted by group theory were observed and assigned on the basis of scattering tensors. Further support for the present assignments of the β-AgI optic lattice modes comes from the approximately linear relations found between the squares of the optic-mode frequencies of a number of wurtzite-type crystals and their respective reciprocal reduced masses. The frequencies of the two silent optic lattice modes were determined by a normal coordinate treatment.