Vibrational frequencies and structural determination of trimethylphosphine oxide

The normal mode frequencies and corresponding vibrational assignments of trimethylphosphine oxide are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of eight types of motion (P-C stretch, PO stretch, C-H stretch, C-P-C bend, PO bend, H-C-H bend, CH3 wag, and CH3 twist) utilizing the C3v symmetry of the molecule. Calculations were performed at the Hartree-Fock, DFT (B3LYP), and MP2 levels of theory using the standard 6-311G** basis. Theoretical results were successfully compared against available experimental data. Infrared intensities and Raman activities were calculated and reported.