Calculation of small arsenic and antimony chalcogenide clusters with an application to vitreous chalcogenide structure

Small clusters of the As/Sb-S/Se system that is of importance for simulation of elementary structure units of chalcogenide glasses are calculated using DFT technique. Different structures of As2Xn- and Sb2Xn- (X=S,Se) with proper hydrogen termination are compared by the total electronic energy values. The most stable As-X structures are of corner-sharing (CS) type (i.e. the elementary AsX3-pyramids linked via one X atom, and in the case of Sb-X family a new asymmetrical Sb2Se3 cluster appears rather than its compact (C3h) form.