ULTRAVIOLET PHOTODISSOCIATION OF GAS-PHASE ALCOHOLS, AMINES, AND NITROALKANES

The 193-nm photochemistry of alcohols, amines, and nitroalkanes in the C-3-C-6 size range is presented. The photolysis products are photoion ized with coherent vacuum ultraviolet radiation and analyzed by time-o f-flight mass spectrometry. For alcohols and amines, C-C bond dissocia tion competes with dissociation of the alpha(C-C) bond is preferred ov er other locations. Dissociation of a C-C bond is suppressed when a me thyl radical would be produced. This behaviour is similar to that obse rved for other substituted alkanes. Nitroalkanes exhibit both C-N and N-O bond dissociation pathways. Their low bond energies cause a substa ntial amount of internal energy to be partitioned among the primary ph otodissociation products. Under collision-free conditions, the alkyl r adicals produced from these molecules undergo extensive secondary frag mentation. If the photodissociation step is performed in a free jet ex pansion, collisional cooling stabilizes the primary products and allow s large species, such as intact pentyl and hexyl radicals, to be detec ted.