Rate constants for removal of CH(D)(ν= 0 and 1) by collisions with N2, CO, O2, NO and NO2at 298 K and with CO2at 296 ⩽T/K ⩽ 873

Abstract

A combination of laser photolysis and laser-induced fluorescence has been used to study removal rate constants of CH(ν= 0 and 1) radicals in collisions with N2, CO, O2, NO and NO2 at room temperature and with CO2 in the temperature range 296–873 K. The removal rate constants of CD(ν= 0 and 1) in collisions with O2, NO, NO2 and CO2 are also measured at room temperature. Removal rate constants for CH(ν= 0) with N2 and CO are found to be pressure dependent, whereas those for CH(ν= 1) are found to be pressure independent and significantly faster than those measured for the unexcited radicals. Removal rate constants for all CH radical species in collisions with O2, NO and NO2 are found to be very similar. In the case of NO and NO2, the corresponding rate constants are close to the hard-sphere collisional rate constant, indicating that these reactions proceed on attractive potential energy surfaces with little or no barrier to reaction. Removal rate constants for CH(ν= 0) with CO2 are found to be pressure independent at room temperature and to have a complex temperature dependence.