VIBRATIONAL DYNAMICS OF THE BENZENE...ARGON COMPLEX

A section of the potential energy surface of the benzene...argon complex corresponding to the argon versus benzene intermolecular vibrational modes has been determined by fitting the existing ab initio data with the use of two different empirical potentials. From these potential energy sections, using an approximate vibrational Hamiltonian, the intermolecular vibrational energy levels have been evaluated and compared with available spectral and previous theoretical data for C6H6...Ar-40. The stretching fundamental frequency has been found to be in excellent agreement with the literature data. The bending (nearly degenerate) frequencies, however, have been predicted to be significantly higher than those from literature. A reassignment of the observed absorption based on our predictions has led to a complete agreement between theory and experiment. We feel that this casts doubt on the previous vibrational assignment of the observed transitions.