Investigation of Single-Vibronic-Level Fluorescence Lifetimes of Jet-Cooled S_1 trans-Stilbene above the Isomerization Barrier
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The fluorescence lifetimes of jet-cooled trans-stilbene were measured for twenty eight S<sub>1</sub> vibronic levels in the 1300—1700 cm<sup>−1</sup> region above the 0–0 transition. All fluorescence decay curves were well fitted to single exponential functions in the 0—3 ns time region. It was found that the fluorescence lifetime decreases monotonically with the increase of the excess vibrational energy. No anomalous lifetime dependence on the vibronic level was observed. The (time-integrated) dispersed fluorescence from the corresponding vibronic levels was also measured. The excitation of all twenty eight levels gave indistinguishable fluorescence spectra exhibiting only broad features, indicating that the IVR rate is much larger than the radiative decay rate regardless of the fundamental, overtone or combination levels. No direct evidence supporting the existence of a mode-selective isomerization channel was obtained.
- Bulletin of the Chemical Society of Japan
Bulletin of the Chemical Society of Japan 69(4), 925-931, 1996-04-15
The Chemical Society of Japan