Fluorescence Lifetimes of Vibronic States of Naphthalene Vapor in the Region of Excitation from 3080–2150 Å

Fluorescence lifetimes of naphthalene vapor have been measured for narrow band excitation ranging from the first to third excited singlet states. It is found that the inverse lifetimes 1 / τ vary linearly with increasing excitation energy when exciting within the first two bands. For excitation within the third band, the variation is approximately exponential. An attempt is made to interpret the results in terms of theories of radiative and nonradiative transitions.