The dissociative electroionization of ammonia and ammonia-d3. III. The N+ dissociation channel. general conclusions about the dissociation of NH3+

Abstract

The dissociative ionization of NH 3 is investigated in its N + dissociation channel in the 20-50 eV electron energy range. Both the translational energy distribution and the appearance energies are measured. The kinetic energy versus appearance energy plot reveals seven N + producing processes. Near the onset (22.5-24.0 eV) dissociative autoionization occurs whereas direct dissociative ionization produces N + in the 24.5-30 eV range. Above 35 eV mainly N + /H + ion pairs are formed at the expense of doubly ionized states. The dissociative electroionization work on NH 3 being completed, a review of the results is presented.

The threshold-photoelectron spectrum of NH3

“…3, the onset energies for NH 2 + and NH + fragment ions are inserted. From the foregoing discussion, autoionization would presumably contribute to the decay of NH 3 + in both channels.…”

“…1. This spectrum exhibits three bands covering roughly the energy ranges of the 2 A l , the à 2 E and the 2 A 1 states of NH 3 + at about 11, 16 and 25 eV, respectively. However, on the low-energy side of the second band, and starting at 13 eV, a fairly intense shoulder is observed in the threshold-photoelectron spectrum.…”

“…For this purpose, first the photoionization efficiency curves of NH 3 and its three isotopomers have been measured in the energy range of the first ionic 2 A 1 state [5]. The abundant autoionization structure has been analyzed in terms of Rydberg series converging to the first ionization limit.…”

“…In the framework of our study devoted to the dissociative ionization of NH 3 [1][2][3], the photoionization efficiency and the translational energy of NH 2 + and NH + fragment ions were measured. Weak structures were observed in the photoion yield curve NH 2 + above the onset energy at 15.75 eV [4].…”

About the double ionization of ammonia and carbon dioxide. A comparison between photoionization and electron impact

“…The dissociations of NH 3 2+ into (i) doubly ionized species [1] and (ii) pairs of singly ionized ions were examined by the same method [2][3][4]. The translational energy distributions of the fragments were measured in the same energy range.…”