Vibrational predissociation of ArHF: a test of global semiempirical potential energy surfaces

Abstract

Vibrational spectra and vibrational predissociation dynamics of the ArHF complex in the lowest van der Waals levels corresponding to the vibrational states of the HF fragment v = 0–7 are investigated using an accurate quantum mechanical method and recent three-dimensional potential energy surfaces (PES). The results demonstrate the accuracy of the semiempirical diatomics-in-molecule and empirically corrected ab initio PES's and allow for better understanding of the sensitivity of the vibrational predissociation lifetimes and product state distributions to the interaction potential. Main features of the fragmentation dynamics such as near-resonant vibration-to-rotation energy transfer, strong variation of the predissociation lifetimes with excitation of the van der Waals vibrational modes, and rapid increase of the decay rates with vibrational excitation of HF are analyzed.