Abstract
This study discusses the effect of As content addition on the glass density, molar volume, compactness and optical properties of A s x S e 80 − x S 20 ( 0.0 ≤ x ≤ 55 at % ) glasses. The coordination number of Se and S atoms is the same, i.e. NSe = NS = 2, while, NAs = 3. Thus, the coordination number of the present glass increases with increasing the As content. Values of the glass density, compactness and width of localized states increase whereas, values of the molar volume (Vm), optical band gap (Eg) and Tauc parameter ( β ) decrease with the addition of As content. In this study, there is a stoichiometries glass at 24 at% As content with Se-S and As-Se bonds. The obtained results are consistent with each other and are discussed in detail based on the chemical bonds of the glasses as well as the Mott and Davis model.