Journal of Chemical Physics, Vol.110, No.20, 9956-9960, 1999
Hydrogen atom release from methyl groups of energized molecules
Three diverse molecules, 2,3,4,5,6-pentafluorotoluene (PFT), trimethylamine (TMA), and methyl bromide were irradiated by weak 193.3 nm light. In each case hydrogen atoms were released, as the major channel for PFT and as a minor channel for the two others. The low average translational energy release, the isotropic angular distribution, and the linear excimer power dependence all lead to the conclusion that the dissociation is from a very hot ground state. The unimolecular dissociation is less selective than in the more usual unimolecular processes at much lower energies. During these experiments an unusual multiphoton dissociation was found. Focusing 205.1 nm light on TMA produces H atoms with an average kinetic energy of 4.2 +/-0.5 eV.