The generation of CH(X 2Π,v″,N″) fragments in the photolysis of CH2(1 3B1) radicals

Abstract

Ground state methylene, CH2(1 3B1), was shown to dissociate into CH(X 2Π, v″, N″)+H fragments by excitation via the first triplet absorption continuum around 200 nm. Triplet CH2 was generated in the 351 nm photolysis of ketene. CH(X) fragments were formed in the 193 nm photolysis of these radicals and were detected by laser induced fluorescence at around 430 nm. The relative populations of the v″=0 and 1 vibrational states, and the rotational and Λ-doublet levels of these states were characterized. These results are compared with those given in the literature by ab initio and dynamics calculations for the absorption and dissociation of triplet CH2. Further comparisons are made with the photofragmentations H2O→OH(X 2Π)+H and NH2→NH(A 3Π)+H.