STRUCTURE OF CHALCOGENIDE GLASSES IN As-S-Se SYSTEM INVESTIGATED BY RAMAN SPECTROSCOPY AND FIRST PRINCIPLE CALCULATION

We report an investigation of Raman spectroscopy on the structure of As40SxSe60-x glasses prepared by conventional melt-quenching techniques with As, S and Se of 99.99% purity. And vibrational modes of AsSnSe3-n clusters were calculated by Gaussian software based on Density functional theory (DFT). It can be found that the calculated data of basic cluster models are in excellent agreement with observed Raman spectra and we found the frequency variation of main vibrational modes for four basic AsSxSe3-xpyramids can be explained by force constant and reduced mass, according to the molecular spectroscopy theory. Finally, the shift of main Raman scattering frequency of structural units of AsSnSe3-n pyramids in the Raman spectroscopy of As40SxSe60-x glasses can is attributed to the alteration of the nearest neighbor local surroundings with different ratios of S/Se.