Electron impact dissociation of the NH3 molecule: Absolute and relative cross sections for NH*(c 1Π,A 3Π), NH+*(C 2Σ+, B 2Δ,A 2Σ−), and NH*2(A 2A1) fragment emissions

The emission spectrum between 2700 and 5000 Å following single electron impact on ammonia has been investigated. Emission bands of the electronically excited NH(c 1Π,A 3Π), NH+(C 2Σ+,B 2Δ,A 2Σ−), and NH2(Ã 2A1) fragments have been identified and absolute emission cross sections have been determined at 100 eV incident energy. Relative cross sections as a function of the impact energy reveal information about the excitation mechanisms of the parent molecule. Conclusions can be drawn on the dissociation process by a comparison of the observed appearance potentials with thermochemical thresholds and with the results of photodissociation experiments.