Cross Sections and Rate Coefficients for Rotational Excitation of HeH+ Molecule by Electron Impact

Khamesian, Marjan; Ayouz, Mehdi; Singh, Jasmeet; Kokoouline, Viatcheslav

doi:10.3390/atoms6030049

Cited by 8 publications

(5 citation statements)

References 32 publications

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“…In a previous study [19] (hereafter referred to as paper I), we reported cross sections and rate coefficients for vibrational excitation for transitions between the five lowest vibrational levels. In a further study [20] (hereafter referred to as paper II), we presented similar data for rotational transitions in collisions of 4 HeH + with electrons. In the present study, as a follow-up of papers I and II, we determine cross sections and rate coefficients for vibrational and rotational (de-)excitation for collisions of the four stable HeH + isotopologues with electrons.…”

Section: Introductionmentioning

confidence: 88%

Cross Sections and Rate Coefficients for Rovibrational Excitation of HeH+ Isotopologues by Electron Impact

Ayouz

Kokoouline

2019

Atoms

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Cross sections and thermal rate coefficients for rotational and vibration excitation of the four stable isotopologues of the 4 HeH + ion by electron impact are presented. The data are calculated using a previously developed theoretical approach. The obtained rate coefficients are fitted to analytical formulas with the 10–10,000 K interval of applicability. These present results could be useful in tokamak plasma and astrophysical modeling and can help in the detection of these species in the interstellar medium.

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Section: Introductionmentioning

confidence: 88%

Cross Sections and Rate Coefficients for Rovibrational Excitation of HeH+ Isotopologues by Electron Impact

Ayouz

Kokoouline

2019

Atoms

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“…50 100 500 2000 5000 0 1 2 3 4 5 6 7 electrons, for k e (j → j ) we used the approximations given by [29]. Since, the rates of collisional de-excitations by electrons and atomic hydrogen are proportional to their number densities,…”

Section: Heh + Collisional (De)excitation In Dark Agesmentioning

confidence: 99%

“…The population of the rotational levels in the epoch of Dark Ages is defined by collisions with photons of the cosmic microwave background (CMB), free electrons, ions and atoms. Calculations of coefficients for rotational and vibrational excitation/de-excitation rates by electrons are performed by [4,24,29,51]. However, up to date, there are no estimations for HeH + rotational excitation/deexcitation by collisions with atomic hydrogen.…”

Section: Introductionmentioning

confidence: 99%

Thermal and resonant emission of dark age halos in the rotational lines of HeH+

et al. 2020

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We present the main features of thermal and resonant emission for one of the first radiating molecules, the helium hydride ion (HeH + ), from dark ages halos on the stage of the early Universe. Evaluating the optical depth, thermal and resonant brightness temperatures and spectral fluxes of dark ages halos is based on computing the cross-sections and rate coefficients of excitation/deexcitation of the lowest five rotational states of HeH + by inelastic collisions with atomic hydrogen. It was shown that in Dark Ages the collisional excitation/de-excitation by atoms of neutral hydrogen and electrons are competitive, but in the denser regions, e.g. virialized halos, the contribution of collisions with atomic hydrogen is larger. We demonstrate the peak time dependence in the thermal and resonance luminosities evolution of halo in HeH + lines, and the optimization of observations can be made concerning for redshift.

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“…Combinations of the FT approach with multichannel quantum defect theory (MQDT) [6,7] have been previously applied to treat numerous electron-cation collision and molecular photofragmentation systems (see, * roman.curik@jh-inst.cas.cz e.g., Refs. [8][9][10][11][12][13][14][15][16][17]) and still more applications can be found in Rydberg spectroscopy [7]. The cornerstone of these studies is the body-frame quantum defect (or phase shift) µ(R, ) that describes a phase gained by the scattered (or Rydberg) electron inside the molecular core.…”

Section: Introductionmentioning

confidence: 99%

Backpropagated frame transformation theory: A reformulation

2020

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The energy-dependent frame transformation theory of Greene 1990 [Phys. Rev. A 42, 6946 (1990)] is extended to yield quantitatively accurate description of the dissociative recombination process. Evidence is presented to show that direct application of the original theory leads to inaccurate cross sections. A major revision, based on an interaction-free back propagation of the Born-Oppenheimer solutions, markedly improves the frame transformation theory, reducing its average error by orders of magnitude. The original theory and its extension are tested on the previously explored 2D model that is tailored to describe the singlet ungerade states of molecular hydrogen. The 2D model can be solved exactly (within the numerical accuracy) without implementing the Born-Oppenheimer approximation. These exact results then serve as a benchmark for the frame transformation theory developed in this paper.

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Cross Sections and Rate Coefficients for Rotational Excitation of HeH+ Molecule by Electron Impact

Cited by 8 publications

References 32 publications

Cross Sections and Rate Coefficients for Rovibrational Excitation of HeH+ Isotopologues by Electron Impact

Cross Sections and Rate Coefficients for Rovibrational Excitation of HeH+ Isotopologues by Electron Impact

Thermal and resonant emission of dark age halos in the rotational lines of HeH+

Backpropagated frame transformation theory: A reformulation

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