Calculation of the vibrational spectra of arsenic sulfide clusters

The aim of our work is the investigation and modeling of arsenic sulfide glasses. In the frame of this program the structures and the vibrational frequencies of some fundamental arsenic sulfides clusters were calculated applying the ab initio Hartree-Fock method with LANL2DZ basis set. Two structures were supposed with two arsenic atoms: a non-branching one (As2S3) and a double pyramid (As2S5) others are an extended pyramid (As4S6) and an extended double pyramid (As6S9) The calculated structures were compared and analyzed. The calculated fundamental frequencies were compared with the experimental far infrared (400-30 cm(-1)) spectra of different types of arsenic sulfides. These were amorphous and crystalline arsenic sulfides and a deposited amorphous arsenic sulfide film. The calculated spectra are in good accordance with the experimental ones, It was concluded based on the far infrared spectra that possibly the two larger clusters take important role in the structure of arsenic sulfide glasses and films. (C) 1999 Elsevier Science B.V. All rights reserved.