Multiphoton ionization of NO/CD_3OH heteroclusters: Observation of [(NO)_n(CD_3O)_x(CD_3OH)_m]~+ cluster ions

摘要

Ion-molecule reactions within heterogeneous NO/CD_3OH cluster ions have been investigated through the use of multiphoton ionization time-of-flight mass spectrometry. For the case of the mixed cluster ions having two or more NO molecules, heterogeneous cluster ions of the form [(NO)_n(CD_3O)_x(CD_3OH)_m]~+, produced by multiple hydrogen atom loss, are observed, In contrast, the generation of [NO(CD_3OH)_m]~+ is predominant in the mixed cluster ions containing one NO molecule. The hydrogen loss reaction proceeds up to z <= n-1 for [(NO)_n(CD_3O)_x(CD_3OH)_m]~+ with the generation of cluster ions possessing an even number of electrons being clearly preferred. These results lead us to conclude that the generation of cluster ions containing the CD_3O species is strongly dependent on the electron configuration and the number of NO molecules in the cluster. Possible mechanisms of generating cluster ions having multiple CD_3O species are discussed in terms of either a prompt multiphoton ionization or photochemical process prior to ionization.