IVR in Overtones of the Acetylenic C-H Stretch in Propyne

Abstract

Quantum calculations are reported for the high-resolution spectra and dynamics of the first and second overtone
\nof the acetylenic C-H stretch (ν_1) in propyne. The calculational method used is similar to that we have used
\nearlier for lower energy states. Lack of low-order Fenni resonances lead to a vibrational superexchange
\nmechanism of decay of the initially populated bright state. The importance of the total density of states and
\nquartic couplings between zeroth-order states is investigated. Comparison with recent experimental results
\nis discussed.