# Collisions of Trapped Molecules With Slow Beams

 Title: Collisions of Trapped Molecules With Slow Beams Author: Dalgarno, Alexander; Tscherbul, Timur V.; Pavlovic, Zoran; Sadeghpour, Hossein R.; Côté, Robin Note: Order does not necessarily reflect citation order of authors. Citation: Tscherbul, Timur V., Zoran Pavlovic, Hossein R. Sadeghpour, Robin Côté, and Alexander Dalgarno. 2010. Collisions of trapped molecules with slow beams. Physical Review A 82(2): 022704. Full Text & Related Files: Dalgarno_Collisions.pdf (575.9Kb; PDF) Abstract: We present a theoretical study of molecular-trap loss induced by collisions with slow atomic beams based on an explicit analysis of collision kinematics in the laboratory frame and a rigorous quantum description of atom-molecule scattering in external fields. The theory is applied to elucidate the effects of nonuniform magnetic and optical trapping fields on low-temperature collisions of OH $$(J=\frac{3}{2},M_J=\frac{3}{2},f)$$ molecules with $$^{4}$$He atoms. Our calculations quantify the extent to which both elastic and inelastic cross sections are suppressed by external trapping fields, clarify the role of small-angle scattering in trap loss, and may benefit future experiments on collisional cooling of molecules in electromagnetic traps. The calculated cross sections for trap loss in $$^{4}$$He + OH collisions are consistent with recent experimental observations at low beam energies [ B. C. Sawyer $$et al.$$ Phys. Rev. Lett. 101 203203 (2008)], demonstrating the importance of including the effects of nonuniform trapping fields in theoretical simulations of cold collision experiments with trapped molecules and slow atomic beams. Published Version: doi:10.1103/PhysRevA.82.022704 Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:5132920

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