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To accurately map weak D2–Ne long-range interactions, we have studied rotationally inelastic cold scattering of D2 prepared in the vibrationally excited (v = 4) and rotationally aligned (j = 2, m) quantum state within the moving frame of a supersonically expanded mixed molecular beam. In contrast to earlier high energy D2–Ne collision experiments, the (j = 2 → j′ = 0) cold scattering produced highly symmetric angular distributions that strongly suggest a resonant quasi-bound collision complex that lives long enough to make a few rotations. Our partial wave analysis indicates that the scattering dynamics is dominated by a single resonant l = 2 orbital, even in the presence of a broad temperature (0–5 K) distribution that allows incoming orbitals up to l = 5. The dominance of a single orbital suggests that the resonant complex stabilizes through the coupling of the internal (j = 2) and orbital (l = 2) angular momentum to produce a total angular momentum of J = 0 for the D2–Ne complex.
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This content will become publicly available on April 28, 2026
Cold collisions of highly vibrationally excited and aligned D2 with Ne
Resonant scattering of highly vibrationally excited and aligned D2 in cold collisions with Ne has recently been probed experimentally using the Stark-induced adiabatic Raman passage technique [Perreault et al., J. Chem. Phys. 157, 144301 (2022)]. A partial-wave analysis and numerical fitting of the experimental data attributed the measured angular distribution to an l = 2 shape resonance near Ec/kB = 1 K (≈0.7 cm−1). Here, we report the computation of a new potential energy surface for the Ne–H2 interaction suitable for the study of collisions between highly vibrationally excited H2/D2 with Ne as well as quantum scattering calculations of stereodynamics of D2 (v = 4, j = 2) + Ne collisions probing Δj = −2 rotational transition in D2. Our results show that collisions are dominated by a strong l = 5 resonance near 3 K (≈2.09 cm−1) and a weaker l = 6 resonance near 8 K (≈5.56 cm−1) and not an l = 2 resonance, as suggested in the analysis of the experimental data. A reasonable agreement between our calculations and the experiments is obtained only when an artificial energy cutoff is applied to the integral over the collision energy to exclude contributions from the l = 5 resonance while retaining contributions from l = 0, 1, and 2. However, our calculations do not support the claim that the measured angular distributions are dominated by a single l = 2 partial-wave resonance characteristic of orbiting collisions.
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- Award ID(s):
- 2409497
- PAR ID:
- 10595607
- Publisher / Repository:
- AIP
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 162
- Issue:
- 16
- ISSN:
- 0021-9606
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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