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arXiv · 2501.05613

Chemistry in a Cryogenic Buffer Gas Cell

Qi Sun·Jinyu Dai·Rian Koots·Benjamin C. Riley·Jesús Pérez-Ríos·Debayan Mitra·Tanya Zelevinsky
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Abstract

Cryogenic buffer gas sources are ubiquitous for producing cold, collimated molecular beams for quantum science, chemistry, and precision measurements. The molecules are typically produced by laser ablating a metal target in the presence of a donor gas. The radical of interest emerges due to a barrier-free reaction or under thermal or optical excitation. High-barrier reactions, such as between Ca and H$_2$, should be precluded. We study chemical reactions between Ca and three hydrogen isotopologues H$_2$, D$_2$, and HD in a cryogenic cell with helium buffer gas. We observe that H$_2$ can serve as both a reactant and a buffer gas, outperforming D$_2$ and HD. We use a reaction network model to describe the chemical dynamics and find that the enhanced molecular yield can be attributed to rapid vibrational excitations of the reactant gas. Our results demonstrate a robust method for generating bright cold beams of alkaline-earth-metal hydrides for laser cooling and trapping.

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Qi Sun, Jinyu Dai, Rian Koots, Benjamin C. Riley, Jesús Pérez-Ríos, Debayan Mitra, Tanya Zelevinsky. 2025-01-09. Chemistry in a Cryogenic Buffer Gas Cell. https://doi.org/10.1021/acs.jpclett.5c02840

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