Investigation of the collisional quenching of CH(<i>A</i> 2Δ and <i>B</i> 2Σ−) by Ar, O2, CS2, alcohol, and halomethane molecules

Abstract

The quenching rate constants of CH(A 2Δ and B 2Σ−) by Ar, O2, CS2, alcohol, and halomethane molecules have been measured at 290 K by using the direct time-resolved technique. The electronically excited CH radicals were produced by laser photolysis of CHBr3 at 266 nm and the time-resolved emissions of CH(A 2Δ and B 2Σ−–X 2Π) were then monitored as a function of time using a fast digital storage oscilloscope coupled with a microcomputer. For a given partner, the collisional removal rate of CH(B 2Σ−) is faster than that of CH(A 2Δ) except for O2.