The UV photolysis of hydrazoic acid

The UV photolysis of HN3 has been studied by observing the temporal decay in the number density of the NH(a 1Δ) product following photolysis and by observing the temporal behavior of the fluorescence from the secondary photolysis product NH2 (? 2A1), both as a function of HN3 pressure. The HN3 was photolyzed at λ?290 nm by pulses from a frequency-doubled, flashlamp-pumped dye laser while the NH(a 1Δ) was probed by laser-induced fluorescence on the NH(c 1π−a 1Δ) band system at 324 nm using a frequency-doubled, nitrogen-pumped dye laser. The data are analyzed to obtain the rate constants k2=18×10−11 cm3 molecule−1 s−1 for the reaction NH(a 1Δ)+HN3→ NH2(? 2A1)+N3 [Eq.(2)], and k4=9.3×10−11 cm3 molecule−1 s−1 for the reaction NH2(? 2A1)+HN3→NH2(? 2B1)+HN3 [Eq.(4a)]→ NH3+N3 [Eq.(4b)].