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arXiv · 1609.01098

Quantum-State Controlled Penning Ionization Reactions between Ultracold Alkali and Metastable Helium Atoms

Adonis Silva Flores·Wim Vassen·Steven Knoop
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Abstract

In an ultracold, optically trapped mixture of $^{87}$Rb and metastable triplet $^4$He atoms we have studied trap loss for different spin-state combinations, for which interspecies Penning ionization is the main two-body loss process. We observe long trapping lifetimes for the purely quartet spin-state combination, indicating strong suppression of Penning ionization loss by at least two orders of magnitude. For the other spin-mixtures we observe short lifetimes that depend linearly on the doublet character of the entrance channel. We compare the extracted loss rate coefficient with recent predictions of multichannel quantum-defect theory for reactive collisions involving a strong exothermic loss channel and find near-universal loss for doublet scattering. Our work demonstrates control of reactive collisions by internal atomic state preparation.

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Adonis Silva Flores, Wim Vassen, Steven Knoop. 2016-09-05. Quantum-State Controlled Penning Ionization Reactions between Ultracold Alkali and Metastable Helium Atoms. https://doi.org/10.1103/physreva.94.050701

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