A theoretical and experimental study of Sb4O6: vibrational analysis, infrared, and Raman spectra

The first ab initio theoretical study of tetraantimony hexoxide (Sb₄O₆) is reported. The normal mode frequencies, intensities, and the corresponding vibrational assignments of Sb₄O₆ in T_d symmetry were calculated using the gaussian 98 set of quantum chemistry codes at the Hartree-Fock (HF)/CEP-121G, Møller-Plesset (MP2)/CEP-121G, and density functional theory (DFT)/B3LYP/CEP-121G levels of theory. 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 (SbOSb stretch, SbOSb bend, and SbOSb wag). Percent relative errors found for the HF, DFT, and MP2 corrected frequencies when compared to experiment are 5.8, 6.1, and 5.7 cm⁻¹, respectively. Electron distributions for selected molecular orbitals are also considered.