Quantum calculations are reported for the high-resolution spectra and
dynamics of the first and second overtone of the acetylenic C-H stretc
h (nu(1)) in propyne. The calculational method used is similar to that
we have-used Lack of low-order Fermi resonances lead to a vibrational
superexchange mechanism of decay of the initially populated bright st
ate. The importance; of the total density of states and quartic coupli
ngs between zeroth-order states is investigated. Comparison with recen
t experimental results is discussed.