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Poster Session

Poster Session I (4pm-6pm CDT)

4:00 pm – 6:00 pm, Tuesday June 4 Session D00
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Stereodynamical control of cold HD+ D2 collisions

Poster 24
Presenter: Bikramaditya Mandal (University of Nevada, Las Vegas)
Authors: James Croft (Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom), Pablo Jambrina (Departamento de Quimica Fisica, University of Salamanca, Salamanca 37008, Spain), Hua Guo (University of New Mexico), F Aoiz (Departamento de Quimica Fisica, Universidad Complutense, Madrid 28040, Spain), Balakrishnan Naduvalath (University of Nevada, Las Vegas)

The Stark-induced adiabatic Raman passage (SARP) technique has become a powerful tool to probe stereodynamics of cold molecular collisions. Recent experiments using SARP techniques have focused on cold collisions of  aligned HD with H2, D2, and He as well as collisions of two aligned D2 molecules. Here, we report full-dimensional quantum calculations of stereodynamic control of rotational quenching of HD(v=1,j=2) by collisions with D2 that is probed experimentally [1,2]. Both △j=-1 and △j=-2 transitions in HD were explored experimentally. The latter can occur with concurrent rotational excitation of D2 from j=0 to 2. Our calculations reveal that this inelastic process has a cross section that is 5 times larger than elastically scattered D2 at collision energies involved in the experiment but it is not considered in the analysis of the experimental data. Differential rates for both horizontal (H-SARP) and vertical (V-SARP) alignments of the HD molecule are computed and compared against experimental findings. While reasonable agreement with experiment is obtained for the △j=-1  transition in HD, strong discrepancy is observed for the △j=-2 transition. The discrepancy persists whether or not the D2 excitation channel is considered in the theoretical simulations. 

[1] W. E Perreault, N. Mukherjee, and R. N. Zare, Quantum control of molecular collisions at 1 kelvin, Science, 358, 356–359, (2017).

[2] W. E Perreault, N. Mukherjee, and R. N. Zare, Cold quantum-controlled rotationally inelastic scattering of HD with H2 and D2 reveals collisional partner re-orientation. Nature Chemistry, 10, 561–567, (2018).

Funding acknowledgement

This work is supported in part by NSF grant No. PHY-2110227 (B.N.) and DoD MURI grant No. W911NF-19-1-0283 (B.N. and H.G.).

POSTERS (157)