Abstract
Raman spectroscopic investigations of vitreous As2S3 and Li2S-As2S3 binary glasses have been carried out. The studies reveal the fact that intermolecular coupling between the AsS3/2 pyramidal units and the As-S-As tri-atomic units in pure As2S3 is weak and that they can be treated independently. Addition of Li2S modifies the network, creating non-bridging sulphurs. Spectra of binary glasses have been understood on the basis of the presence of possible pyramidal units present in these glasses with one, two or three non-bridging sulphurs. A force constant calculation indicates a higher force constant for an As-S− bond compared with an As-S− bond.