Abstract
The dependence of band gap energy (E-g) and glass-transition temperature (T-g) on physico-chemical properties for the (GeS2)(10)(Sb2S3)(90-x)(AgI)(x) (10 <= x <= 50 at%) chalcohalide glasses were theoretically investigated. Chalcohalide glasses have wide technological applications owing to the aptitude of tuning their optical band gap through composition change. Therefore, E-g of the studied chalcohalide glasses was estimated using different methods, and it was turned out that it decreased as the AgI amount increases. This decrease was elucidated in terms of physico-chemical properties. In addition, we determined the positions of conduction band (E-CB) and valence band (E-VB) by using the computed values of E-g. The density and molar volume increased while the packing density decreased by adding AgI. The overall coordination number (CN), crosslinking density (CD), constraints number (N-s), cohesive energy (CE), heat of atomization (H-s) and overall mean bonds energy (E); computed via the chemical bond approach (CBA); decreased with the increment of AgI amount. In contrary, the floppy (F) and mean bonds energy (E-s) increased. Finally, two estimations of T-g were presented based on E and CN. The two estimations showed a decreasing trend when adding AgI content.