We here present ab initio calculations on small AsnSm clusters that are building blocks for the formation of continuous random networks (CRN) generally found in AsxS100-x glasses. The calculations were performed by density functional theory (DFT). Geometries, vibrational frequencies, Raman intensities for the clusters have been calculated using the modified Stuttgart RLC ECP basis set at DFT/B3LYP level. Using the calculated and experimental data the relative contributions of different small clusters in the glasses structure matrix and the implications are discussed.