Continuous random network models for a-as 2s 3

Abstract

Computer transformation techniques have been used to generate five models of a-A2 B3 binary systems, with differing topologies, from three existing continuous random network models. The resulting structures were energy relaxed using bond stretching, bond bending and non-bonded potentials, to yield a variety of model coordinates. The atom-atom distribution functions of these models were then calculated and compared with experimental data for a-As2S3. The agreement in real space was found to be good for one model in particular. Furthermore, when the data were Fourier transformed to give the interference function, it was found that the model succesfully reproduced the experimental diffraction pattern, including the first diffraction peak at about 1 A−1. This feature has been the subject of some controversy, being used as evidence for both the microcrystallite, layer and the outrigger raft representations of the structure of a-As2S3. The models described here do not contain these structural units, and thus this work calls into question previous interpretations based on the first diffraction peak.