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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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This content will become publicly available on May 7, 2027
Full-dimensional potential energy surface for the H2 + N2 system and quantum scattering calculations of collision-induced rotational energy transfer
A full-dimensional global potential energy surface (PES) for the H2 + N2 system is constructed using the permutation invariant polynomial-neural network method, based on high-level ab initio energy points computed at the CCSD(T)-F12a/AVQZ level. To accurately describe the long-range interactions, a multipole expansion parameterized by ab initio data is incorporated into the PES. Quantum close-coupling scattering calculations are reported for rotationally inelastic transitions in H2 + N2 collisions using the full-dimensional PES. Cross sections for rotational excitation of N2 within a rigid rotor model are found to be in excellent agreement with those obtained using a four-dimensional (4D) PES reported by Gomez et al. [Chem. Phys. Lett. 445, 99 (2007)]. Cross sections for pure rotational quenching of H2, as well as quenching of H2 accompanied by rotational excitation of N2, exhibit dense resonance structures. For collision energies above 2.0 cm−1, the results are in close agreement with those obtained using the 4D PES of Gomez et al., including the positions of the sharp resonances. At lower collision energies, however, noticeable differences appear, indicating a strong sensitivity of the resonance features to the PES in this regime. An accurate simulation of energy transfer in collisions between rovibrationally excited H2 and D2 with N2 can now be addressed using the full-dimensional PES reported in this study.
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- Award ID(s):
- 2409497
- PAR ID:
- 10689336
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 164
- Issue:
- 17
- ISSN:
- 0021-9606
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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