Lifetimes of single rotational states in the "channel three" region of C6H6

Lifetimes ofsingle rotational states in the 141 vibrational state ofbenzene, C6H6, at 3412 cmI excess energy were measured. The lifetimes depend strongly on the rotational quantum number J and we find them to agree with our recent homogeneous linewidth measurements of the same states. We present a coupling scheme including the coupling of the excited narrow light zero order state with a broadened dark background state. The broadening is due to a fast electronic nonradiative relaxation process typical for astate containing quanta of out-of-plane modes. It is demonstrated that the observed J dependence is due to perpendicular Coriolis coupling in the weak coupling limit. The IVR process resulting from this coupling explains the onset of"channel three" in a natural way without any further mystery states in the model.