THE VIBRATIONAL-SPECTRA OF THE BORON HALIDES AND THEIR MOLECULAR-COMPLEXES .1. ABINITIO PREDICTIONS OF THE VIBRATIONAL-SPECTRA OF BORON-TRIFLUORIDE, CHLORODIFLUORIDE, FLUORODICHLORIDE AND TRICHLORIDE

The intramolecular vibrational band wavenumbers and infra-red and Raman intensities of boron trifluoride, chlorodifluoride, fluorodichloride and trichloride were computed using ab initio molecular orbital theory, at the self-consistent-field and second order Moller-Plesset levels of theory, employing the 6-31G* basis set. The calculated results were compared with experimental ones, where available. Force constants, dipole moment derivatives and atomic polar tensors were derived and trends in their values, and in those of the wavenumbers and intensities, were rationalized on the basis of the varying molecular electronic properties resulting from successive fluorine-chlorine substitution.