The kinetics of the OH + HCNO reaction was studied. The total rate constant was measured by LIF detection of OH using two different OH precursors, both of which gave identical results. We obtain k = (2.69 +/- 0.41) x 10(-12) exp[(750.2 +/- 49.8)/T] cm(3) molecule(-1) s(-1) over the temperature range 298-386 K, with a value of k = (3.39 +/- 0.3) x 10(-11) cm(3) molecule(-1) s(-1) at 296 K. CO, H(2)CO, NO, and HNO products were detected using infrared laser absorption spectroscopy. On the basis of these measurements, we conclude that CO + H(2)NO and HNO + HCO are the major product channels, with a minor contribution from H(2)CO + NO.

The kinetics of the CN + HCNO reaction were studied using laser-induced fluorescence and infrared diode laser absorption spectroscopy. The total rate constant was measured to be k(T) = (3.95 +/- 0.53) x 10(-11) exp[(287.1 +/- 44.5)/T] cm3 molec(-1) s(-1), over the temperature range 298-388 K, with a value of k1 = (1.04 +/- 0.1) x 10(-10) cm3 molec(-1) s(-1) at 298 K. After detection of products and consideration of secondary chemistry, we conclude that NO + HCCN is the only major product channel.

The kinetics of the NCO + HCNO reaction were studied using infrared diode laser absorption spectroscopy. The total rate constant was measured to be k(1) = (1.58 +/- 0.20) x 10(-11) cm(3) molecule(-1) s(-1) at 298 K. After detection of products and consideration of secondary chemistry (primarily O + HCNO and CN + HCNO), we conclude that NO + CO + HCN is the major product channel (phi = 0.92 +/- 0.04), with a minor contribution (phi = 0.04 +/- 0.02) from CO2 + HCNN.

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The kinetics of the O + HCNO reaction were investigated by a relative rate technique using infrared diode laser absorption spectroscopy. Laser photolysis (355 nm) of NO2 was used to produce O atoms, followed by O atom reactions with CS2, NO2, and HCNO, and infrared detection of OCS product from the O + CS2 reaction. Analysis of the experiment data yields a rate constant of k1= (9.84 +/- 3.52) x 10-12 exp[(-195 +/- 120)/T)] (cm3 molecule-1 s-1) over the temperature range 298-375 K, with a value of k1 = (5.32 +/- 0.40) x 10-12 cm3 molecule-1 s-1 at 298 K. Infrared detection of product species indicates that CO producing channels, probably CO + NO + H, dominate the reaction.

The reaction of the CN radical with O(2) was studied using infrared diode laser absorption spectroscopy. Detection of NO and secondary N(2)O products was used to directly measure the product branching ratio. After consideration of possible secondary chemistry and comparison to kinetic modeling simulations, the branching ratio of the CN + O(2) reaction into the NO + CO channel was determined to be phi (NO + CO) = 0.20 +/- 0.02, with little or no temperature dependence over the range 296-475 K.

IR diode laser spectroscopy was used to detect the products of HCNO (fulminic acid) photolysis at 248 nm. Five product channels are energetically possible at this photolysis wavelength: O + HCN, H + (NCO), CN + OH, CO + NH, and HNCO. In some experiments, isotopically labeled (18)O2, (15)N(18)O and C2D6 reagents were included into the photolysis mixture in order to suppress and/or isotopically label possible secondary reactions. HCN, OC(18)O, C(18)O, NCO, DCN, and NH molecules were detected upon laser photolysis of HCNO/reagents/buffer gas mixtures. Analysis of the yields of product molecules leads to the following photolysis quantum yields: ϕ1a (O + HCN) = 0.39 ± 0.07, ϕ1b (H + (NCO)) = 0.21 ± 0.04, ϕ1c (CN + OH) = 0.16 ± 0.04, ϕ1d (CN + NH(a(1)Δ)) = 0.19 ± 0.03, and ϕ1e (HNCO) = 0.05 ± 0.02, respectively. The uncertainties include both random errors (1σ) and consideration of major sources of systematic error. In conjunction with the photolysis experiment, the H + HCNO reaction was investigated. Experimental data demonstrate that this reaction is very slow and does not contribute significantly to the secondary chemistry.