Associative ionization in collisions of , with and

Naji, Adham; Olamba, K; Chenu, J P; Szűcs, Sándor; Brouillard, F.

doi:10.1088/0953-4075/31/21/018

Cited by 6 publications

(11 citation statements)

References 10 publications

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“…The corresponding AI process (9), as investigated experimentally by Naji et al [18] appears much weaker in comparison. The MN /AI ratio, depending on the theoretical approach, ranges from 2000 to 4000 at 100 meV, an order of magnitude typically encountered with light colliding partners.…”

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confidence: 84%

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Investigation of critical parameters controlling the efficiency of associative ionization

Padellec

Launoy

Dochain

et al. 2017

J. Phys. B: At. Mol. Opt. Phys.

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This paper compiles our merged-beam experimental findings for the associative ionization (AI) process from charged reactants, with the aim of guiding future investigations with e.g. the double electrostatic ion storage ring DESIREE in Stockholm. A reinvestigation of the isotopic effect in H−(D−) + He+ collisions is presented, along with a review of and NO+ production by AI involving ion pairs or excited neutrals, and put in perspective with the mutual neutralization and radiative association reactions. Critical parameters are identified and evaluated for their systematic role in controlling the magnitude of the cross section: isotopic substitution, exothermicity, electronic state density, and spin statistics.

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mentioning

confidence: 84%

“…With the help of the merged ion beam apparatus implanted in Louvain-La-Neuve, Belgium, we were able to investigate various combinations of reactants to form diatomics and triatomics [16][17][18][19][20][21][22][23]. Since technical details, not relevant here, were described elsewhere, for instance in [17], they will not be repeated.…”

Section: Introductionmentioning

confidence: 99%

Investigation of critical parameters controlling the efficiency of associative ionization

Padellec

Launoy

Dochain

et al. 2017

J. Phys. B: At. Mol. Opt. Phys.

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“… References: 1 –Launay et al (1991); 2 – same as corresponding H reaction, but scaled by D reduced mass; 3 –Schulz & Asundi (1967); 4 –Xu & Fabrikant (2001); 5 –Poulaert et al (1978); 6 –Naji et al (1998); 7 –Stancil et al (1996). …”

Section: Methodsmentioning

confidence: 99%

Is H⁺₃cooling ever important in primordial gas?

Glover¹,

Savin²

2009

Monthly Notices of the Royal Astronomical Society

126

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Studies of the formation of metal‐free Population III stars usually focus primarily on the role played by H2 cooling, on account of its large chemical abundance relative to other possible molecular or ionic coolants. However, while H2 is generally the most important coolant at low gas densities, it is not an effective coolant at high gas densities, owing to the low critical density at which it reaches local thermodynamic equilibrium (LTE) and to the large opacities that develop in its emission lines. It is therefore possible that emission from other chemical species may play an important role in cooling high‐density primordial gas. A particularly interesting candidate is the H+3 molecular ion. This ion has an LTE cooling rate that is roughly a billion times larger than that of H2, and unlike other primordial molecular ions such as H +2 or HeH+, it is not easily removed from the gas by collisions with H or H2. It is already known to be an important coolant in at least one astrophysical context – the upper atmospheres of gas giants – but its role in the cooling of primordial gas has received little previous study. In this paper, we investigate the potential importance of H+3 cooling in primordial gas using a newly developed H+3 cooling function and the most detailed model of primordial chemistry published to date. We show that although H+3 is, in most circumstances, the third most important coolant in dense primordial gas (after H2 and HD), it is nevertheless unimportant, as it contributes no more than a few per cent of the total cooling. We also show that in gas irradiated by a sufficiently strong flux of cosmic rays or X‐rays, H+3 can become the dominant coolant in the gas, although the size of the flux required renders this scenario unlikely to occur.

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“…d Notes: 1, fit to Scholz and Walters (1991); 2, assumed the same as the corresponding H reaction; 3, Black (1981); 4, fit to Voronov (1997); 5, Black (1981), dielectronic recombination (DR); 6, fit to , radiative recombination (RR); 7, fit to Badnell (1998), DR;8, Savin (2002), total rate coefficient is the sum of the two lines; 9, fit to Croft et al (1999b); 10, same as corresponding H reaction, but scaled by D reduced mass; 11, determined from cross section of Croft et al (1999a); 12, same as (22), but magnitude scaled by (21)/(20); 13, determined from cross section of Osterbrock (1989); 14, Galli and Palla (1998); 15, determined from cross section of ; 16, Wang and Stancil (2002); 17, determined from cross section of Naji et al (1998);18, Carota et al (1999);19, Dunne et al (2001), with the former rate coefficient for T < 280 K and the latter for T > 280 K; 20, Bodo et al (2001b); 21, Krohn et al (2001).…”

Section: Standard Chemistry In the Early Universementioning

confidence: 99%

“…This is about 25% smaller than the value adopted by resulting in a proportional decrease in the HD fractional abundance. As in the hydrogen chemistry, we added the recently measured associative ionization reaction (Naji et al 1998), but found it to have a negligible effect.…”

Section: Deuterium Chemistrymentioning

confidence: 99%

Atomic and Molecular Processes in the Early Universe

Lepp

2005

AIP Conference Proceedings

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Most of the information about the environment of the early Universe comes to us from radiation emitted from atoms and molecules. An understanding of the relevant atomic and molecular processes is needed to correctly interpret this radiation. Atomic and molecular process also control the evolution of the early Universe. In this paper, we review the atomic and molecular processes that are important in the early Universe.

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Associative ionization in collisions of , with and

Abstract: Measurements were carried out using merged beams and chopping the negative beam to evaluate the background. The measurements cover the barycentric energy range from 0.07 to 10 eV. The four cross sections were, within experimental error, equal both in magnitude and energy dependence.

Cited by 6 publications

References 10 publications

Investigation of critical parameters controlling the efficiency of associative ionization

Investigation of critical parameters controlling the efficiency of associative ionization

Is H⁺₃cooling ever important in primordial gas?

Atomic and Molecular Processes in the Early Universe

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Associative ionization in collisions of , with and

Abstract: Measurements were carried out using merged beams and chopping the negative beam to evaluate the background. The measurements cover the barycentric energy range from 0.07 to 10 eV. The four cross sections were, within experimental error, equal both in magnitude and energy dependence.

Cited by 6 publications

References 10 publications

Investigation of critical parameters controlling the efficiency of associative ionization

Investigation of critical parameters controlling the efficiency of associative ionization

Is H+3cooling ever important in primordial gas?

Atomic and Molecular Processes in the Early Universe

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Product

Resources

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Is H⁺₃cooling ever important in primordial gas?