Abstract: | Rate coefficients, k1, for the reaction OH + HONO → H2O + NO2, have been measured over the temperature range 298 to 373 K. The OH radicals were produced by 266 nm laser photolysis of O3 in the presence of a large excess of H2O vapor. The temporal profiles of OH were measured under pseudo-first-order conditions, in an excess of HONO, using time resolved laser induced fluorescence. The measured rate coefficient exhibits a slight negative temperature dependence, with k1 = (2.8 ± 1.3) × 10?12 exp((260 ± 140)/T) cm3 molecule?1 s?1. The measured values of k1 are compared with previous determinations and the atmospheric implications of our findings are discussed. |