Rovibrational quenching rate coefficients of HD in collisions with He

J. L. Nolte, P. C. Stancil, T. G. Lee, N. Balakrishnan, R. C. Forrey

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Along with H2, HD has been found to play an important role in the cooling of the primordial gas for the formation of the first stars and galaxies. It has also been observed in a variety of cool molecular astrophysical environments. The rate of cooling by HD molecules requires knowledge of collisional rate coefficients with the primary impactors, H, He, and H 2. To improve knowledge of the collisional properties of HD, we present rate coefficients for the He-HD collision system over a range of collision energies from 10-5 to 5 × 103 cm -1. Fully quantum mechanical scattering calculations were performed for initial HD rovibrational states of j = 0 and 1 for v = 0-17 which utilized accurate diatom rovibrational wave functions. Rate coefficients of all Δv = 0, -1, and -2 transitions are reported. Significant discrepancies with previous calculations, which adopted a small basis and harmonic HD wave functions for excited vibrational levels, were found for the highest previously considered vibrational state of v = 3. Applications of the He-HD rate coefficients in various astrophysical environments are briefly discussed.

Original languageEnglish (US)
Article number62
JournalAstrophysical Journal
Volume744
Issue number1
DOIs
StatePublished - Jan 1 2012

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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