A comparative study of the low energy HD+<i>o</i>-/<i>p</i>-H2 rotational excitation/de-excitation collisions and elastic scattering

Sultanov, Renat A.; Guster, Dennis; Adhikari, Sadhan K.

doi:10.1063/1.3699203

Cited by 8 publications

(6 citation statements)

References 52 publications

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“…The coordinates for DCO + + H 2 differ from those for HCO + + H 2 only by small displacement of the centre of mass in the DCO + molecules. The old coordinates were expressed as a function of the new one from geometrical considerations (Sultanov, Guster & Adhikari 2012), and a new grid of energies was generated and fitted using the same expression 1. The influence of this correction in the PES is small (see Fig.…”

Section: R E S U Lt Smentioning

confidence: 99%

Rotational relaxation of HCO+ and DCO+ by collision with H2

Denis-Alpizar

Stoecklin

Dutrey

et al. 2020

Monthly Notices of the Royal Astronomical Society

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The HCO+ and DCO+ molecules are commonly used as tracers in the interstellar medium. Therefore, accurate rotational rate coefficients of these systems with He and H2 are crucial in non-local thermal equilibrium models. We determine in this work the rotational de-excitation rate coefficients of HCO+ in collision with both, para- and ortho-H2, and also analyze the isotopic effects by studying the case of DCO+. A new four-dimensional potential energy surface from ab initio calculations was developed for the HCO+ – H2 system, and adapted to the DCO+– H2 case. These surfaces are then employed in close-coupling calculations to determine the rotational de-excitation cross-sections and rate coefficients for the lower rotational states of HCO+ and DCO+. The new rate coefficients for HCO+para-H2 were compared with the available data, and a set of rate coefficients for HCO+ + ortho-H2 is also reported. The difference between the collision rates with ortho- and para-H2 is found to be small. These calculations confirm that the use of the rate coefficients for HCO+ + para-H2 for estimating those for HCO++ortho-H2 as well as for DCO++para-H2 is a good approximation.

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Section: R E S U Lt Smentioning

confidence: 99%

Rotational relaxation of HCO+ and DCO+ by collision with H2

Denis-Alpizar

Stoecklin

Dutrey

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…Then, collisions between HD and these projectiles have been the object of numerous studies . For HD–He collisions, both experiments and computational works are available since the 1970s − and, more recently, they have been studied in the astrophysical context. , For HD–H 2 , new calculations have been recently published in the cold temperature regime, − and seminal works can be found earlier. , …”

Section: Introductionmentioning

confidence: 99%

Rotational Excitation of HD by Hydrogen Revisited

et al. 2018

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The HD molecules are key species for the cooling of pristine gas at temperatures below 100 K. They are also known to be key tracers of H2 in protoplanetary disks and thus, they can be used as a measure of protoplanetary disks mass. Accurate modeling of the cooling mechanism and of HD abundance in astrophysical media requires a proper modeling for its excitation by both radiative and collisional processes. Here, we report quantum time-independent calculations of collisional rate coefficients for the rotational excitation of HD by H for temperatures ranging from 10 to 1000 K. The reactive and hydrogen exchange channels are taken into account in the scattering calculations. New exact quantum results are compared to previous calculations performed neglecting reactive and exchange channels. We found that for temperatures higher than ∼300 K, the impact of these channels on the rate coefficients cannot be neglected. Such results suggest that the new HD–H collisional data have to be used for properly modeling HD cooling function and HD abundance in all the astrophysical environments where HD plays a role, e.g. in photon-dominated regions, protoplanetary disks, early Universe chemistry, and primordial star forming regions.

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“…Quantum-mechanical closecoupling calculations for three-dimensional collisions of para-H 2 and ortho-H 2 with HD are performed in Ref. 11,13,18,19,21 , where the HD-H 2 potential is derived from the H 2 -H 2 potential.…”

Section: Introductionmentioning

confidence: 99%

Low temperature HD+ortho-/para-H₂inelastic scattering of astrophysical interest

Sultanov¹,

Guster²,

Adhikari³

2015

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

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State-selected total cross sections and thermal rate coefficients are computed for the HD + ortho-/para-H 2 rotational energy transfer collision at low temperatures: 2 K T 300 K. A modified H 2 -H 2 potential energy surface (PES) devised by Hinde is used for this pure quantum-mechanical dynamical computation. A comparison of the new results for the HD + ortho-/para-H 2 scattering problem and previous calculations computed with the use of other older PESs is presented and discussed.

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A comparative study of the low energy HD+o-/p-H2 rotational excitation/de-excitation collisions and elastic scattering

Cited by 8 publications

References 52 publications

Rotational relaxation of HCO+ and DCO+ by collision with H2

Rotational relaxation of HCO+ and DCO+ by collision with H2

Rotational Excitation of HD by Hydrogen Revisited

Low temperature HD+ortho-/para-H₂inelastic scattering of astrophysical interest

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A comparative study of the low energy HD+o-/p-H2 rotational excitation/de-excitation collisions and elastic scattering

Cited by 8 publications

References 52 publications

Rotational relaxation of HCO+ and DCO+ by collision with H2

Rotational relaxation of HCO+ and DCO+ by collision with H2

Rotational Excitation of HD by Hydrogen Revisited

Low temperature HD+ortho-/para-H2inelastic scattering of astrophysical interest

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Low temperature HD+ortho-/para-H₂inelastic scattering of astrophysical interest