Quantum Yield of NO3 from Peroxyacetyl Nitrate Photolysis

Peroxyacetyl nitrate (PAN) vapor was photolyzed at 248 nm and the NO 3 photoproduct was detected by laser-induced fluorescence. The quantum yield for the production of NO 3 was determined by comparison to N 2 O 5 photolysis data taken under identical experimental conditions. Contributions to the observed laser induced fluorescence were found to arise from excited-state photoproducts such as NO 2 *. The excited-state fluorescence contributions were investigated, and a data analysis methodology was established to minimize their effects. The average of data collected over a range of total pressures, precursor concentrations, and buffer gases was 0.3 ± 0.1 for the NO 3 quantum yield, where the quoted statistical uncertainty represents two standard deviations. This result, combined with our previously reported value of 0.83 ± 0.09 for the NO 2 quantum yield from the photolysis of PAN, suggests that NO 2 and NO 3 represent the only nitrogen-containing products in the 248 nm photolysis of PAN. The atmospheric implications of a NO 3 producing channel in PAN photolysis are considered.