PACKING OF Ar AROUND CO AS DEDUCED FROM IR LINESHAPE ANALYSIS
Ohio State University
A theory of the influence of solvent packing around small solute molecules in cryogenic matrices has been successfully applied to interpret IR spectra of CO trapped in Ar. Spectra of neat CO co-deposited with Ar as well as CO generated photochemically from a variety of sources such as OCS and metal carbonyls have been measured with high resolution and successfully interpreted on the basis of model potential energy functions for the Ar-CO interaction. Neat CO is found to lie in two types of doubly-substituted sites, while CO generated from OCS is born into a singly-substituted site that is formed irreversibly. Metal carbonyls produce CO in a variety of sites with similarities as well as differences to those formed in neat CO or CO from OCS. The general character of the trapping sites and the nature of the "cage effect" illucidated by these measurements will be discussed as well.
Author Institution: Dartmouth College, Hanover, NH 03755; University of Colorado, Boulder, CO 80309