Rate constants for removal of CH(D)(ν= 0 and 1) by collisions with N2, CO, O2, NO and NO2 at 298 K and with CO2 at 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.