Infrared chemiluminescence studies of H atom reactions with Cl2O, ClNO, F2O, CF3OF, ClO2, NO2, and ClO

Abstract

Infrared chemiluminescence from the HF, HCl, and OH products has been used to measure the nascent vibrational distributions and the rate constants at 300 K for the title reactions in a fast flow reactor. The ClO reaction was observed as a secondary step in the ClO2 and Cl2O systems. The reactions proceeding by a direct mechanism, Cl2O, ClNO, OF2, and CF3OF release relatively small fractions, ∼0.37, of the available energy as HCl or HF vibrational energy with narrow distributions, in accord with the dynamics associated with the H atoms on a repulsive potential surface. The ClO2 and NO2 reactions, which proceed by short lived intermediates, release a larger fraction of vibrational energy to OH and with broad distributions. Although the data for the ClO reaction are not definitive, the OH formation channel is the more important by a factor of 4–5. The NO2 reaction was studied in direct comparison with Cl2 to choose the best Einstein coefficients of OH by comparing the OH and HCl formation rate constants.