A photochemical study of nitrogen dioxide using a pulsed ruby laser

Abstract

At higher pressures of N02 the decay was markedly nonexponential, emission maxima actually occurring. The data is consistent with a consecutive stepwise vibrational deactivation mechanism wherein the detection system is more sensitive to the radiation from intermediate states than to the initially formed excited state. Analysis of the data, using different theoretical models for vibrational deactivation to relate the rate constants to one another, gave values for the vibrational deactivation rate constant in the order of 4 x l0-10 cm3/part-sec. This effect was observed only for addition of NO2 enhancement of the V -> T transfer and is probably a result of rate due to the chemical bond potential available to the N02-N02 pair. The vibrational deactivation rate constants for the other added gases must be much less than the corresponding electronic deactivation rate constants.