https://doi.org/10.1140/epjp/s13360-026-07511-0
Regular Article
Systematic investigation into the rotational relaxation behavior of H2(1,8) molecules induced by collision with H2, Ar, N2, NO, and CO
1
Xinjiang Key Laboratory of Solid State Physics and Devices, Xinjiang University, 830017, Urumqi, Xinjiang Uygur Autonomous Region, China
2
School of Physical Science and Technology, Xinjiang University, 830017, Urumqi, Xinjiang Uygur Autonomous Region, China
a
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Received:
15
July
2025
Accepted:
28
February
2026
Published online:
9
March
2026
Abstract
This study systematically investigated the collisional-induced energy transfer between H2(v = 1, J = 8) molecules and H2, Ar, N2, NO, and CO at 297 K.Time-resolved coherent anti-Stokes Raman scattering measurements on H2(1,8) were performed in H2–Ar, N2, NO, and CO mixtures at 400 Torr, enabling accurate determination of collisional relaxation rate coefficients for H2(1,8)–M interactions. Experimental results show that in H2–M systems, the collisional self-relaxation rate coefficient for H2–H2 are (1.95 ± 0.08), (0.45 ± 0.09), (0.84 ± 0.08), (1.26 ± 0.07), and (2.10 ± 0.06) × 10−14 cm3 s−1, respectively; while the relaxation rate coefficients for H2(1,8) colliding with Ar, N2, NO, and CO are (2.90 ± 0.19), (4.48 ± 0.17), (4.24 ± 0.14), and (4.83 ± 0.11) × 10−14 cm3 s−1. The results show that the collisional relaxation rate coefficient in the H2–CO system is 66.6%, 7.8%, and 13.9% higher than in the H2–Ar, H2–N2, and H2–NO systems, respectively, confirming that CO most significant enhancement on the rotational relaxation of H2(1,8). The rotational relaxation mechanism of H2(1,8) in H2–M systems (M = N2, NO, CO) was systematically investigated by measuring the time evolution of H2(v = 1, J = 8, 6, 4) population distributions. The study shows that increasing the molar fraction of the acceptor molecule M leads to distinct changes in the relaxation mechanism of H2(1,8) across different systems: in H2–N2, it shifts from predominantly single-quantum to slightly dominant multi-quantum relaxation; in H2–NO, from balanced to single-quantum dominance; and in H2–CO, from multi-quantum to single-quantum dominance. Analysis of the dynamic collision process shows that near-resonant energy transfer dominates the rotational relaxation of H2(1,8).
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
