Excited state dynamics of NO3

Abstract

The fluorescence decay of NO₃ excited to vibronic levels between the origin at 661.9 and ∼606 nm is measured and found to be nonexponential. An exponential fit to the long‐lived portion of the decay gives an apparent, collision‐free lifetime of 340±20 μs. Electronic quenching rates have been measured for a variety of collision partners including He, N₂, O₂, C₃H₈, and HNO₃. Our results are interpreted in terms of the Douglas effect, i.e., an extensive coupling of excited electronic levels with nonemissive vibronic levels of the ground electronic state. This coupling is likely responsible for the anomalously long lifetime and the apparent diffuseness of the absorption spectrum.