TEMPERATURE-DEPENDENCE OF THE LIFETIME OF NAPHTHALENE B-1(3U) UNDER BOLTZMANN CONDITIONS

The lifetime of naphthalene 1B3u was measured in the gas phase under Boltzmann conditions (argon pressures > 400 Torr) over the temperature range 368-460 K. The results were found to agree well with calculations based on an assumed energy-dependent decay constant derived from the analysis by Schlag et al. of the decay of single vibronic levels. The Boltzmann distribution over the vibronic levels of the excited state was calculated using densities of vibrational states obtained from a direct count procedure. The results support Schlag's contention that the energy dependence of the single vibronic level lifetimes in naphthalene is predominantly determined by the Franck-Condon factors; they also indicate that no additional mechanism is needed to explain the observed temperature effects. © 1979.