Ra. Brownsword et al., BRANCHING RATIO FOR THE H+NCO CHANNEL IN THE 193 NM PHOTODISSOCIATIONOF HNCO, Chemical physics letters, 249(3-4), 1996, pp. 162-166
The H atom quantum yield phi(H) and the average product translational
energy were determined for the HNCO --> H(S-2) + NCO(X(2)II) photodiss
ociation channel at room temperature for a photolysis wavelength of 19
3 nm. HNCO was photolyzed using an ArF excimer laser and nascent H ato
ms were detected by vacuum-UV-laser-induced fluorescence at the Lyman-
alpha transition. With a calibration method using HCl photolysis as a
source of well-defined H atom concentrations, a value of phi(H) = 0.20
+/- 0.04 for the H atom quantum yield was measured. From H atom Doppl
er profiles, measured under single collision conditions, the fraction
f(T) of the available energy released as product translational energy
was determined to be f(T)(H + NCO)= 0.69 +/- 0.09.