ANILINE-CH4S1 VIBRATIONAL DYNAMICS STUDIED WITH PICOSECOND PHOTOELECTRON-SPECTROSCOPY

Intramolecular vibrational energy redistribution (IVR) and vibrational predissociation (VP) are measured for a number of vibronic states in the S1 electronic state of the aniline-CH4 complex. The detailed dynam ics are monitored using picosecond threshold photoelectron spectroscop y which is shown to be a sensitive probe of van der Waals molecule dyn amics. For the lowest vibrational states accessed, the 6a0(1)BAR and 6 a0(1)BAR + 24 cm-1 bands, both IVR and VP are observed and their rates are independently determined. At higher excess energy, IVR becomes th e rate limiting step and the rate for VP cannot be measured independen tly. The results are interpreted using a serial dissociation mechanism with a simple kinetic model description. The rates of the reaction ar e modeled using standard Rice-Ramsperger-Kassel-Marcus (RRKM) theory w hich qualitatively predicts rates consistent with the experimental obs ervations.