ATOM ASYMMETRIC-TOP VANDERWAALS COMPLEXES - ANGULAR-MOMENTUM COUPLING IN AR-H2O

A model for the vibrational states of atom-asymmetric top van der Waals complexes is developed, based on hindered rotation of the asymmetric top in the complex. The pattern of energy levels expected from such a model is described, and the dependence of the spectrum on features of the potential energy surface is explored. The selection rules arising from the model are presented. The model is used to interpret the infrared spectra of Ar-H2O reported by Cohen et al. [J. Chem. Phys. 89, 4494 (1988)], and preliminary information on the effective bending potential for Ar-H2O is obtained. The potential is very isotropic, varying by only about 40 cm-1 as a function of the angular coordinates. Predictions of band origins for other allowed infrared transitions are given. © 1990 American Institute of Physics.