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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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Resonant cold scattering of highly vibrationally excited D2 with Ne
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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- Award ID(s):
- 2110256
- PAR ID:
- 10440341
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 157
- Issue:
- 14
- ISSN:
- 0021-9606
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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