Vibrational Structure and Predissociation of Ar-CO₂by CO₂Symmetric Stretching Mode Coupled with Ar Motion

Abstract

The computationally simple quantum mechanical method (VSCF-DWB-IOS) has been applied to studying the Ar-CO 2 vibrational predissociation phenomenon. The new methodology utilizes the vibrational self-consistent field method to determine the vibrational structure of the van der Waals complex, the distorted-wave Born approximation for dissociating process, and the infinite-order sudden approximation for the continuum dissociating product of CO 2. The dissociation due to the coupling of the symmetric stretching vibrational motion of CO 2 with the motion of the Ar van der Waals mode has been extensively investigated. The lifetimes of transient excited vibrational states, linewidths of absorption peak, and the rotational state distributions of the product, CO 2 have been computed. It has been found that the lifetime of the Ar-CO 2 in excited vibrational state is very long compared with that of triatomic van der Waals complexes and the product CO 2 carries a major portion of dissociation energy as a rotational energy.