Gas-phase infrared spectra and Ab initio study of phosphorus (III) oxyhalides OPBr and OPI

Phosphorus (III) oxyhalides O=P-X molecules (X=Br, I) were produced by an on-line process. Two routes have been followed to generate OPBr. The OPBr was passed over heated KI to produce OPI. The low-resolution gas-phase Fourier transform infrared spectra reported here for the first time, show three bands centered at 1268.1, 1253 and 408.2 cm-1. The first two bands are associated with the O=P fundamental stretching mode of OPBr and OPI respectively. The third band is connected to the P-Br stretching mode of OPBr. Ab initio Hartree-Fock (HF) self-consistent-field (SCF) molecular orbital (MO) calculations, and Moeller-Plesset second-order perturbation theory (M P2) were performed to determine the geometry, total energy and vibrational frequencies of OPBr and OPI