Angular behavior of E-doublets in Raman spectra of tetragonal gyrotropic crystals

Abstract

Angular dependencies of the Raman modes frequency on direciton of phonon wave vector q in tetragonal gyrotropic crystals TeO2, ZnP2, and CdP2 were investigated and compared. We observed two completely different types of angular behavior of E-doublets splitting in depending on relative contributions of spatial dispersion and long-range Coulomb interaction. The explanation of apparent anomalous dependence of E-doublet 122 cm-1 splitting on q in TeO2 is proposed.