Formation of NO3 in the Photolysis of N2O5

DOI: 10.5176/2339-5060_1.1.6

Authors: Man-Nung Su and Jim Jr-Min Lin

Abstract:

The spectra of excited nitrate radicals (NO3*) produced from the photolysis of N2O5 at 248 and 193 nm are reported for the first time. We measured the time-resolved absorption spectra from 400 to 700 nm and separated the contributions of excited- and ground-state species. The spectra of NO3* are broad and featureless in this spectral region. An induction period was observed before the formation of thermalized NO3, consistent with the existence of NO3* that is then quenched by collisions with the buffer gas. We re examined the kinetics of the formation of the room-temperature NO3 and determined the formation rate constants in N2 at 248 and 193 nm photolysis to be (7.1±1.0)×10−13 and (7.9±1.0)×10−13 cm3molecule−1s−1, respectively. We also measured the relative formation rate constants in O2, Ar, CO2 and SF6 buffer gases.

Keywords: excited states, photochemistry, transient absorption, vibrational relaxation