Electric-Field-Controlled Cold Dipolar Collisions between Trapped <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>CH</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:mi mathvariant="normal">F</mml:mi></mml:mrow></mml:math> Molecules
Manuel Koller, F. Jung, J. Phrompao, Martin Zeppenfeld, Isabel Rabey, Gerhard Rempe
Abstract
Reaching high densities is a key step toward cold-collision experiments with polyatomic molecules. We use a cryofuge to load up to $2\ifmmode\times\else\texttimes\fi{}{10}^{7}$ ${\mathrm{CH}}_{3}\mathrm{F}$ molecules into a boxlike electric trap, achieving densities up to ${10}^{7}/{\mathrm{cm}}^{3}$ at temperatures around 350 mK where the elastic dipolar cross section exceeds $7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}\text{ }\text{ }{\mathrm{cm}}^{2}$. We measure inelastic rate constants below $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\text{ }{\mathrm{cm}}^{3}/\mathrm{s}$ and control these by tuning a homogeneous electric field that covers a large fraction of the trap volume. Comparison to ab initio calculations gives excellent agreement with dipolar relaxation. Our techniques and findings are generic and immediately relevant for other cold-molecule collision experiments.