A Theoretical Study of As4O6: Vibrational Analysis, Infrared and Raman Spectra.

The first complete ab initio theoretical study of tetraarsenic hexoxide (As 4 O 6 ) is reported. The normal mode frequencies, intensities and the corresponding vibrational assignments of As 4 O 6  in  T d  symmetry were calculated using the gaussian 98 set of quantum chemistry codes at the HF, MP2, and DFT/B3LYP levels of theory using the 6-311G* basis set. By comparison to experimental data deduced by our laboratory and others, correction factors for the calculated vibrational frequencies were determined and compared. Normal modes were decomposed into three non-redundant motions (As–O–As stretch, As–O–As bend, and As–O–As wag). Percent relative errors found for the HF, DFT, and MP2 corrected frequencies when compared to experiment are 3.6, 4.6, and 5.0, respectively. Electron distributions for selected molecular orbitals are also considered.