Dissociative electron attachment to nitromethane

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 ∼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 ΔfHg°(CH2NO2−) = –1.71 eV, ΔfHg°(H−) = 2.09 eV, ΔfHg°(CH2−) = 3.5 eV and ΔfHg°(NO−) = –1.93 eV, respectively.