Raman scattering studies of SnS2and SnSe2

The Raman spectra of 2H and 4H-SnS2 and 6Hb-SnSe2 have been studied at room and liquid nitrogen temperatures. Interpretation of the observed Raman modes is given in terms of the different symmetries of these polytypes and the more important short-range forces involved in determining the energies of the higher-energy phonon modes are identified by the use of a simple force-constant model.