Abstract Propargyl (HC [TRIPLE BOND] C [BOND] CH 2) and methyl radicals were produced through the 193-nm excimer laser photolysis of mixtures of C 3 H 3 Cl/He and CH 3 N 2 CH 3/He, respectively. Gas chromatographic and mass spectrometric (GC/MS) product analyses were employed to characterize and quantify the major reaction products. The rate constants for propargyl radical self-reactions and propargyl-methyl cross-combination reactions ...