Long-wavelength phonons inTlSbS2: Raman-active modes

Abstract
A low-temperature investigation of the first-order Raman spectrum of TlSbS2 has been performed, and all Raman modes predicted by group-theory arguments have been resolved. Marked selection rules have been found which are not usual for a crystal with triclinic symmetry. Also, a fine structure, indicative of Davydov-like partners, has been found at low temperatures. This behavior is discussed in terms of the most important chains that underlie the crystal structure.