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arXiv:physics/0210019 · Physical Review A

Inelastic collision rates of trapped metastable hydrogen

David Landhuis, Lia Matos, Stephen C. Moss, Julia K. Steinberger, Kendra vant, Lorenz Willmann, Thomas J. Greytak, Daniel Kleppner

Published Feb 28, 2003• 13 citations
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Abstract

We report the first detailed decay studies of trapped metastable $(2S)$ hydrogen. By two-photon excitation of ultracold H samples, we have produced clouds of at least $5\ifmmode\times\else\texttimes\fi{}{10}^{7}$ magnetically trapped $2S$ atoms at densities greater than $4\ifmmode\times\else\texttimes\fi{}{10}^{10}{\mathrm{cm}}^{\ensuremath{-}3}$ and temperatures below $100\ensuremath{\mu}\mathrm{K}.$ At these densities and temperatures, two-body inelastic collisions of metastable atoms are evident. Experimental values for the total two-body loss rate constant are ${K}_{2}{=1.8}_{\ensuremath{-}0.7}^{+1.8}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}{\mathrm{cm}}^{3}{\mathrm{s}}^{\ensuremath{-}1}$ at $87\ensuremath{\mu}\mathrm{K}$ and ${K}_{2}{=1.0}_{\ensuremath{-}0.5}^{+0.9}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}{\mathrm{cm}}^{3}{\mathrm{s}}^{\ensuremath{-}1}$ at $230\ensuremath{\mu}\mathrm{K}.$ These results are in the range of recent theoretical calculations for the total $2S\ensuremath{-}2S$ inelastic rate constant. The metastable clouds were excited in a gas of ground-state $(1S)$ hydrogen with peak densities reaching $7\ifmmode\times\else\texttimes\fi{}{10}^{13}{\mathrm{cm}}^{\ensuremath{-}3}.$ From the one-body component of the metastable decay, we derive experimental upper limits for ${K}_{12},$ the rate constant for loss due to inelastic $1S\ensuremath{-}2S$ collisions.

DOI
10.1103/physreva.67.022718

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