Hyperfine and Zeeman interactions in ultracold collisions of molecular hydrogen with Li atoms
POSTER
Abstract
Cold collisions involving molecular hydrogen (H2) have been the subject of significant interest across various contexts, from astrochemistry of the interstellar medium to controlled chemistry at extremely low temperatures. However, previous theoretical studies of such collisions neglected the effects of hyperfine interactions and Zeeman shifts, which could be substantial at ultracold conditions (the hyperfine structure of ortho-H2 in the first rotational state is on the order of 20 μK).
We present a rigorous quantum scattering study of the effects of hyperfine and Zeeman interactions on cold Li-H2 collisions in the presence of an external magnetic field using a recent ab initio potential energy surface. We obtain a favorable ratio of the cross sections for elastic to inelastic collisions for the low-field-seeking Zeeman states of H2. We discuss the importance of the spin-dependent Li-H2 interaction, the role of collisions conserving the projection of the total nuclear spin of H2, and the implications for sympathetic cooling of molecular hydrogen by lithium in a magnetic trap.
We present a rigorous quantum scattering study of the effects of hyperfine and Zeeman interactions on cold Li-H2 collisions in the presence of an external magnetic field using a recent ab initio potential energy surface. We obtain a favorable ratio of the cross sections for elastic to inelastic collisions for the low-field-seeking Zeeman states of H2. We discuss the importance of the spin-dependent Li-H2 interaction, the role of collisions conserving the projection of the total nuclear spin of H2, and the implications for sympathetic cooling of molecular hydrogen by lithium in a magnetic trap.
*The research is financed from the budgetary funds on science projected for 2019-2023 as a research project under the "Diamentowy Grant" program. P.W. is supported by the National Science Centre in Poland, Project No. 2019/35/B/ST2/01118. The research is a part of the program of the National Laboratory FAMO in Torun, Poland. Calculations have been partially carried out using resources provided by the Wroclaw Centre for Networking and Supercomputing [60], Grant No. 546. We gratefully acknowledge Poland's high-performance computing infrastructure PLGrid (HPC Centers: ACK Cyfronet AGH, PCSS, CI TASK) for providing computer facilities and support within computational Grant No. PLG/2022/015576.
Presenters
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Hubert Jozwiak
- Nicolaus Copernicus University in Torun