Ab initio determination of the infrared phosphine torsion spectrum in vinylphosphine with ZPE correction

The potential energy curve for the hindered internal rotation of the phosphine group in vinylphosphine is determined at MP2 and MP4 levels with a 6-311G(3df,p) basis set, and the vibrational zero point energy correction. From the optimal geometries of each conformation the kinetic parameter is calculated as a function of the rotation angle. By solving the Schrödinger equation for the internal rotation, the torsional levels and torsional wave functions are obtained. From these results and the electric dipole moment variations, the torsional spectrum in the far infrared is synthesized. A c-type band progression for the syn–syn transitions is encountered. This result agrees fairly well with those obtained for ethylphosphine, the spectrum of which is well known.9 page(s