Ionization of ammonia and deuterated ammonia by electron impact from threshold up to 180 eV

Märk, T. D.; Egger, F.; Chéret, M.

doi:10.1063/1.435321

Cited by 93 publications

(29 citation statements)

References 23 publications

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“…22.6 ± 0.1 eV and the most recent value reported by Morrison and Traeger [5]. The largest discrepancy is found with the onset determined by Mark et al [6] at 29.5 ± 0.5 eV. It has to be pointed out that these authors measured systematically higher onset energies compared to other published values.…”

Section: Discussioncontrasting

confidence: 54%

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

Locht

Momigny

1988

Chemical Physics

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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.

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Section: Discussioncontrasting

confidence: 54%

“…The dissociation of NH 3 leading to the production of N + has mainly been investigated by electroionization by several groups [3][4][5][6]. However none of these provided any data about the translational energy carried away by N + at the numerous reported threshold energies.…”

Section: Introductionmentioning

confidence: 99%

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

Locht

Momigny

1988

Chemical Physics

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“…The dissociation of NH 3 into H + and H 2 + has been investigated by a few groups. Appearance energies were measured but very briefly discussed without kinetic energy measurements.…”

Section: Introductionmentioning

confidence: 99%

The dissociative electroionization of ammonia and ammonia-d3. II. The H+ and H2+ dissociation channels

et al. 1988

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“…For comparison, previous 70 eV electron impact data [12] and the most recent 40.8 eV photoionization data [13] are included in this table. No significant…”

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confidence: 99%

“…For comparison, previous 70 eV electron impact data [12] and the most recent 40.8 eV photoionization data [13] are included in this table. No significant discrepancies are observed between electron impact data, especially when it is noticed that in the present work no extraction field is applied to the ion beam.…”

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confidence: 99%

The double ionization of ammonia. Its dissociation into the doubly ionized fragment N2+

Locht

Momigny

1987

Chemical Physics Letters

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The double ionization and dissociation of NH 3 into the doubly ionized fragment N 2+ is investigated by electron impact. Two double ionization energies of NH 3 are directly measured at 34.8 ± 0.2 and 39.4 ± 0.5 eV. A third critical energy observed at 66 eV is assigned to a NH 3 2+ state whose ionization energy is at 61 eV. Two appearance energies are observed for the N 2+ ion at 65.9 ± 1.7 and 74.3 ± 2.6 eV. The translational energy distribution of N 2+ is shown to be essentially thermal. The former onset is ascribed to the dissociation of the 61 eV state of NH 3 2+ , the latter originates from a doubly ionized NH 3 2+ state at 70 eV.Compared to the literature dedicated to ionization and dissociation of molecular cations, the abundance of work devoted to double ionization is very small. This statement has to be ascribed to the generally low abundance of double ionized species. Until recently, only electron impact and high-energy ion impact allowed us to observe these species. The improvement of high-energy light sources, e.g. He (II) resonance lamps, and even more the increasing number of electron synchrotron radiation facilities, allowed us to reach photon energies far above the 21.22 eV energy limit. These developments were the starting point of an increasing number of publications in the field of double and even multiple ionization.During the last few years, the double ionization of NH 3 has been studied by several techniques including double charge transfer spectroscopy (DCTS) [ 2+ into singly as well as doubly ionized fragment ions. The dissociation of doubly charged NH 3 into pairs of singly charged ions has recently been studied by photoionization using the photoion-photoion coincidence (PIPICO) technique [3]. Several theoretical calculations have been devoted to the NH 3 dication, using a variety of techniques [1,[6][7][8].The aim of this work was to investigate the double ionization of NH 3 , as well as its dissociation, as a complementary source of information for the detailed study of the dissociative ionization of NH 3 and ND 3 in the 15-45 eV energy range. This work is still in progress [9]. The doubly ionized species, observed in the mass spectrum of NH 3 , are included in this work.The experimental apparatus and the experimental conditions used in the course of this work have been described in detail elsewhere [10]. At the present time the instrument is fully computer controlled [11], The ammonia and ammonia-d 3 , purchased from Air Liquide and Merck, Sharp & Dohme respectively, are distilled under high vacuum to reduce the traces of water in the samples. Special care is taken to reduce the background signal of N + and O + by prolongated bake-out at 250° C. Owing to the low intensity of the signals, each first differentiated ionization efficiency curve was scanned 600-700 times, requiring 20-30 h. This operation was repeated at least 10-15 times. The onset energies reported in this work are averaged values from these 10-15 independent measurements. The error limits mentioned are the standard devia...

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Ionization of ammonia and deuterated ammonia by electron impact from threshold up to 180 eV

Cited by 93 publications

References 23 publications

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

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

The dissociative electroionization of ammonia and ammonia-d3. II. The H+ and H2+ dissociation channels

The double ionization of ammonia. Its dissociation into the doubly ionized fragment N2+

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