ROVIBRATIONAL QUENCHING RATE COEFFICIENTS OF HD IN COLLISIONS WITH He
- Department of Physics and Astronomy and Center for Simulational Physics, University of Georgia, Athens, GA 30602 (United States)
- Allison Physics Laboratory, Auburn University, Auburn, AL 36849 (United States)
- Department of Chemistry, University of Nevada-Las Vegas, Las Vegas, NV 89154 (United States)
Along with H{sub 2}, 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{sub 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{sup -5} to 5 Multiplication-Sign 10{sup 3} cm{sup -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 {Delta}v = 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.
- OSTI ID:
- 22004344
- Journal Information:
- Astrophysical Journal, Vol. 744, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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