A theoretical study of As4S4:: Bonding, vibrational analysis and infrared and Raman spectra

The structure, bonding, electron distribution, normal mode frequencies and the corresponding vibrational assignments of tetrarsenic tetrasulfide (As4S4) in D-2d symmetry are examined theoretically using the GAUSSIAN 98 set of quantum chemistry codes at the HF, MP2 and B3LYP(DFT) levels of theory using the standard 6-311G* basis. By comparison to experimental normal mode frequencies deduced by Chapman [Spectrochim. Acta 24A(1968)1687] correction factors for predominant vibrational motions are determined and compared. Normal modes were decomposed into four nonredundant motions {As- As stretch, As- S stretch, As-S-As bend, and As-S-As wagging modes}. (C) 2002 Elsevier Science B.V. All rights reserved.