Dissociative electron attachment to nitromethane

摘要

Dissociative electron attachment (DEA) measurements to nitromethane, CH3NO2, in the gas phase have been revisited by making use of a high mass-resolution sector field instrument. Anion efficiency curves for 16 negatively charged fragments have been measured in the electron energy region from about 0 to 16 eV with an energy resolution of similar to 1 eV. Eight new anions have been detected, CH2NO2-, CHNO2-, CH2NO-, H2NO-, CH3-, CH2-, CH- and H-. The five most dominant product anions are NO2-, O-, OH-, CN- and CNO-, all of them featuring two high-energy resonances at about 5 eV and 10 eV. Formation of CH2NO2- at low electron energies has been explained in terms of DEA to highly vibrationally excited molecules. The standard enthalpy of formation of CH2NO2- and H-, CH2- and NO- radicals have been estimated as Delta H-f(g)degrees(CH2NO2-) = -1.71 eV, Delta H-f(g)degrees(H-) = 2.09 eV, Delta H-f(g)degrees(CH2-) = 3.5 eV and Delta H-f(g)degrees(NO-) = -1.93 eV, respectively.