Dissociative recombination and excitation of N + 2

Norén, C.; Yousif, F. B.; Mitchell, James B.

doi:10.1039/f29898501697

Cited by 35 publications

(21 citation statements)

References 3 publications

(3 reference statements)

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“…The first set of N 2 + data from Noren et al [1989], reportedly corresponding to the hottest ions, was nearly identical to the original MEIBE results of Mul and McGowan [1979], to the new MEIBE results we have presented in this paper, and to the CRYRING results of Peterson et al [1998]. By manipulating the source conditions, they produced two additional sets of data, each reportedly with subsequently vibrationally cooler ions.…”

Section: N2+ O2+ and No+ Dr Rate Coefficientssupporting

confidence: 68%

Dissociative recombination of N₂⁺, O₂⁺, and NO⁺: Rate coefficients for ground state and vibrationally excited ions

Sheehan¹

2004

J. Geophys. Res.

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We review recent advances in the study of the dissociative recombination of molecular ions with electrons with a primary emphasis on experimental studies. In particular, we focus on previous experimental measurements of recombination rates for N2+, O2+, and NO+ ions. In the context of this review, we present temperature dependent rate coefficients from recent merged beam studies of the dissociative recombination of N2+, O2+, and NO+ ions with electrons. Identifying underlying physical differences between the various experimental techniques enables a discussion of the effects of vibrational excitation on the dissociative recombination of these major ionospheric species of ions. For T < 1200 K, we conclude that the recombination rates for N2+, O2+, and NO+ ions in the ground electronic and vibrational states respectively are 2.2 × 10−7 (Te/300)−0.39 cm3 s−1, 1.95 × 10−7(Te/300)−0.70 cm3 s−1, and (3.5 ± 0.5) × 10−7(Te/300)−0.69 cm3 s−1. Vibrational excitation is shown to play a significant role in laboratory measurements of these recombination rates. For each of these species, vibrationally excited ions yielded a lower recombination rate than the ground state. We also discuss the recombination of these species of ions for T > 1200 K.

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Section: N2+ O2+ and No+ Dr Rate Coefficientssupporting

confidence: 68%

Dissociative recombination of N₂⁺, O₂⁺, and NO⁺: Rate coefficients for ground state and vibrationally excited ions

Sheehan¹

2004

J. Geophys. Res.

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“…Yousif and Mitchell speculated that the sharp structures they observed might correspond to doubly excited resonant neutral states and stated that similar structures have been seen in measurements on N~ [27] and H[ 28]. However, we have shown here that the presence of such structures in the fixed-nuclei cross sections will not manifest itself in the observable cross section unless these states are relatively independent of internuclear separation in the Franck-Condon region.…”

Section: Discussionsupporting

confidence: 73%

Dissociative excitation ofHeH+by electron impact

1991

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We report the results of an ab initio variational treatment of electron-impact cross sections for the process e +HeH+~e +He++H for electron energies between 21 eV, the threshold for excitation of the dissociative 1 X+ state, and 26 eV, corresponding to the excitation energy of the first 'X+ excited state. The calculations, which were carried out using a recent modification of the complex Kohn method, employed accurate correlated target wave functions, as well as ab initio optical potentials to incorporate the e6'ect of closed channels. The fixed-nuclei excitation cross sections were found to be dominated by a series of sharp resonance structures. However, when the cross sections are averaged over the Franck-Condon envelope of the ground vibrational state, these sharp features are no longer seen. We conclude that the recent experiments that report structure in the HeH+ dissociation cross section cannot be explained within the context of traditional adiabatic-nuclei theory.PACS number(s): 34.80.Gs

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“…Very narrow structures previously observed in the DR cross section below 1 eV with vibrational relaxed Hg+ [14], Nz+ [15], or NO+ [16] were attributed to mainly destructive interferences of the direct and indirect recombination channels proceeding via vibrational excited Rydberg states with a ground state ion core. These inter ferences manifest themselves mainly by the occurrence of dips or "windows" in the cross section, because the probability for changing the vibrational quantum number by more than one is small [17] or because the opening of additional decay channels leads to higher autoioniza-tion probabilities.…”

mentioning

confidence: 72%

New resonances in the dissociative recombination of vibrationally coldCD+

et al. 1994

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Thy dissociative recombination of vibrationally cold CD+ with electrons in the energy range of 0.01 eV to 60 eV has been measured using the Test Storage Ring in a merged beam arrangement. New resonance structures are observed with prominent peaks at 0.8 eV, 8.6 eV, and 11. 7 eV. While the second and third resonance are readily attributed to direct recombination processes through Rydberg levels with dissociating molecular ion cores, the origin of the Grst resonance structure is not well understood, however, its small width of 0.45 eV is an indication of an indirect recombination process.PACS numbers: 34.80.Gs Although CH+ was one of the first interstellar molecular ions to be observed in the visible part of the spectrum, its overabundance compared to theoretical expectations is still an unresolved problem [1]. The dominant process for removing CH+ from the interstellar medium is the dissociative recombination (DR), CH++e~C +H, and as the temperatures of interstellar clouds are low, the main contribution comes from ions in their vibrational

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Dissociative recombination and excitation of N + 2

Cited by 35 publications

References 3 publications

Dissociative recombination of N₂⁺, O₂⁺, and NO⁺: Rate coefficients for ground state and vibrationally excited ions

Dissociative recombination of N₂⁺, O₂⁺, and NO⁺: Rate coefficients for ground state and vibrationally excited ions

Dissociative excitation ofHeH+by electron impact

New resonances in the dissociative recombination of vibrationally coldCD+

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Dissociative recombination and excitation of N + 2

Cited by 35 publications

References 3 publications

Dissociative recombination of N2+, O2+, and NO+: Rate coefficients for ground state and vibrationally excited ions

Dissociative recombination of N2+, O2+, and NO+: Rate coefficients for ground state and vibrationally excited ions

Dissociative excitation ofHeH+by electron impact

New resonances in the dissociative recombination of vibrationally coldCD+

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Resources

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Dissociative recombination of N₂⁺, O₂⁺, and NO⁺: Rate coefficients for ground state and vibrationally excited ions

Dissociative recombination of N₂⁺, O₂⁺, and NO⁺: Rate coefficients for ground state and vibrationally excited ions