Appearance Potential Studies. II. Nitromethane

Abstract

Appearance potentials and excess kinetic energies have been determined for the ions produced by the ionization and dissociation of nitromethane by electron impact in a mass spectrometer. Bond dissociation energies and mechanisms of fragmentation have been deduced where possible. D(CH₃–NO₂) has been found to be 2.56 volts, a value in agreement with thermochemical data. The dissociation and ionization process yielding NO⁺, the most abundant ion in the nitromethane mass spectrum, is believed to yield, at the same time, a CH₃O radical. A new value for the ionization potential of NO₂, 9.91 volts, is reported.