The rotational and vibrational dynamics of argon–methane. II. Experiment and comparison with theory

Abstract

Presented here is a detailed comparison between the experimental near infrared spectrum of argon–methane and the results of a theoretical calculation based upon the methods described in a companion paper, hereafter referred to as paper I [T. G. A. Heijmen et al., J. Chem. Phys. 110, 5639 (1999), preceding paper]. Many of the bands in the spectrum are easily assigned directly from this comparison. The spectrum is shown to be highly sensitive to the anisotropy of the argon–methane potential surface and the agreement with the ab initio spectrum, although not quantitative, is very good. The predissociation linewidths observed in the experimental spectra are found to be strongly dependent upon the symmetry of the excited state. Symmetry considerations place restrictions on the final rotational states that can be accessed, possibly explaining the differences in the lifetimes.