The 193-nm photochemistry of alcohols, amines, and nitroalkanes in the C3–C6 size range is presented. The photolysis products are photoionized with coherent vacuum ultraviolet radiation and analyzed by time-of-flight mass spectrometry. For alcohols and amines, C–C bond dissociation competes with dissociations involving the heteroatom (C–O, O–H, C–N, N–H). Dissociation of the α(C–C) bond is preferred over other locations. Dissociation of a C–C bond is suppressed when a methyl radical would be produced. This behavior is similar to that observed for other substituted alkanes. Nitroalkanes exhibit both C–N and N–O bond dissociation pathways. Their low bond energies cause a substantial amount of internal energy to be partitioned among the primary photodissociation products. Under collision-free conditions, the alkyl radicals produced from these molecules undergo extensive secondary fragmentation. If the photodissociation step is performed in a free jet expansion, collisional cooling stabilizes the primary products and allows large species, such as intact pentyl and hexyl radicals, to be detected.
Philip L. Ross, Scott E. Van Bramer, and Murray V. Johnston, "Ultraviolet Photodissociation of Gas-Phase Alcohols, Amines, and Nitroalkanes," Appl. Spectrosc. 50, 608-613 (1996)