title: Electron induced dissociation in condensed-phase nitromethane I: desorption of ionic fragments.
abstract: Low energy electron induced dissociation of condensed nitromethane was investigated by measuring the electron stimulated desorption of anions and cations from multilayer films of CH(3)NO(2) and CD(3)NO(2), using a recently constructed, high sensitivity time of flight mass spectrometer. The desorbed yields were measured as a function of incident electron energy in the range between 1 to 20 eV and as function of coverage on Pt and Xe substrates. In anion desorption experiments, the following ions were observed: H(-) (D(-)), O(-), OH(-) (OD(-)), CN(-), NCO(-), NO(2)(-), CHNO(2)(-) (CDNO(2)(-)), CH(2)NO(2)(-) (CD(2)NO(2)(-)). Resonant structure seen in all anion yield functions, is attributed to dissociative electron attachment (DEA), though certain anion signals [e.g., OH(-) (OD(-)) and CH(2)NO(2)(-) (CD(2)NO(2)(-))] are likely the result of reactive scattering by O(-) ions. The dominant desorbed cation signals are CD(3)(+) and NO(+), and the appearance potentials of these species were measured to be 12.2 and 11.5 eV, respectively. The present measurements provide information on how the electron-induced dissociation processes of this proto-typical explosive molecule are modulated by the condensed environment and on how initial dissociation events occurring on a particular molecule, may induce further dissociation.
authors.affiliation: Département de médecine nucléaire et radiobiologie, Faculté de médecine, Université de Sherbrooke, Sherbrooke, QC, Canada,J1J 1R7.
authors.forename: Marc
authors.initials: M
authors.lastname: Bazin
authors.forename: Sylwia
authors.initials: S
authors.lastname: Ptasińska
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Bass
authors.forename: Léon
authors.initials: L
authors.lastname: Sanche