ROVIBRATIONAL COUPLING IN THE S1 EXCITED-STATE OF 1-METHYLINDOLE

We have undertaken an extensive study of the spectroscopy and dynamics of the S1-S0 transition in jet-cooled 1-methylindole and 1-methyl(d3) indole. The energy-resolved fluorescence decays resulting from picosec ond excitation of S1 vibrational modes display unusual quantum interfe rence effects which have been attributed to the excitation of a large number of quaside-generate states even at relatively low levels of vib rational excitation. This has been attributed to rovibrational couplin g in which the selection rules are much less restrictive than is norma lly the case with rigid planar molecules. A significant rotational tem perature dependence of the vibrational dynamics has been measured whic h serves to corroborate this model.