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Full-dimensional quantum scattering calculations are reported for rovibrational transitions in HD+HD collisions using a highly accurate interaction potential for the H2–H2 system. Several near-resonant rovibrational transitions are identified that conserve the overall rotational angular momentum and nearly conserve the internal energy of the collision partners. Key anisotropic terms that drive the rotational transitions and angular momentum partial waves that contribute to low-energy resonant features in the energy dependence of the cross-sections are identified. The computed results agree with total cross-sections reported in previous experimental results, including resonant features in the energy dependence of the cross-section. In particular, low-energy cross-sections show a strong resonant feature associated with an l = 3 partial wave in the incident channel. Rate coefficients for several inelastic rotational and rovibrational transitions are reported for temperatures ranging from 0.1 to 200 K, and they display a maximum between 1 and 10 K, reflecting the important contributions from the l = 3 shape resonance that occurs around 2.5 K.
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Rotational quenching of HD induced by collisions with H2 molecules
ABSTRACT Rate coefficients for rotational transitions in HD induced by H2 impact for rotational levels of HD j ≤ 8 and temperatures 10 K ≤ T ≤ 5000 K are reported. The quantum mechanical close-coupling (CC) method and the coupled-states (CS) decoupling approximation are used to obtain the cross-sections employing the most recent highly accurate H2–H2 potential energy surface (PES). Our results are in good agreement with previous calculations for low-lying rotational transitions The cooling efficiency of HD compared with H2 and astrophysical applications are briefly discussed.
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- PAR ID:
- 10108651
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 488
- Issue:
- 1
- ISSN:
- 0035-8711
- Page Range / eLocation ID:
- 381 to 386
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1093/mnras/stz1735
