A DISTRIBUTED GAUSSIAN APPROACH TO THE VIBRATIONAL DYNAMICS OF AR-BENZENE

A method for calculating the vibrational eigenstates of van der Waals clusters is presented and applied to argon-benzene. The method employs the linear variational principle with a nonorthogonal basis set of Gaussian functions in both the stretching and bending coordinates. These localized functions allow greater flexibility than the standard spherical harmonics or Wigner D functions and should be more efficient when the motion is confined to specific regions of the potential energy surface. Calculations are performed on several potential surfaces including two recent fits to a previously published ab initio calculation. Accurate results with rapid convergence are obtained here for the states of zero total angular momentum (J=0). The results agree with calculations recently performed on the same potential surfaces by a different method [J. Chem. Phys. 98, 5327 (1993)] and suggest a reassignment of the experimentally observed bands. An extension of the basis set to nonzero J is presented in the Appendix.