RESONANT RAMAN-SCATTERING STUDIES OF SNS2 CRYSTALS

Details of resonant Raman scattering (RRS) in SnS, single crystals are presented. A detailed investigation of some newly observed features h as been carried out using far-IR (FIR) absorption spectroscopy. A comp arison of RRS and FIR data shows that the new features are IR active m odes, and second-order or combination modes which become allowed under the resonant Raman condition. The resonant behaviour of non-polar mod es is explained using a quasi-two-dimensional approach. Our experiment al data provide a good fit to the theory of RRs at the M1 critical edg e.