TIME-DEPENDENCE OF OH OVERTONE RELAXATION IN THE HYDROPEROXYL RADICAL

The time-dependent relaxation of zero-order O-H vibrational overtone states of nonrotating HO2 on the X2A" double many-body expansion (DMBE)-I potential surface is examined. The time dependence of these states is obtained by expanding them in a large basis of all the bound molecular eigenstates as well as L2 states above dissociation. Franck-Condon factors and survival probabilities are calculated and used to determine the relaxation time scales using techniques described by Heller [E.J. Heller, Phys. Rev. A 35, 1360 (1987)]. For low overtones, the relaxation is very slow and is due mainly to isomerization. Higher O-H overtones relax much more rapidly due to dephasing and intramolecular vibrational relaxation (IVR). The time dependence of several wave packets is depicted in coordinate space.