ANALYSIS OF VIBRATIONAL ABSORPTION INTENSITIES IN BENZENE AND METHYL BENZENES

Vibrational absorption intensities in the gas phase for toluene-d0, toluene-d8 and p-xyelene-d0 have been determined. An optimized set of dipole-moment derivatives associated with aromatic and methyl group vibrations have been determined using an appropriate double-mode refinement process from the experimental infrared intensity data for benzene-d0, toluene-d0 and toluene-d8. The signs of intensity parameters are determined by 4-31G ab initio MO calculations. The set of dipole derivatives is used in predicting the spectrum of p-xylene.