Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 10: Posters Wednesday (Cooling and Trapping, Electron Scattering and Recombination)
A 10.3: Poster
Mittwoch, 4. April 2001, 12:30–15:00, AT3
Calculation of the Li-H triplet scattering length. — •A. S. Dickinson1, F. X. Gadéa2, and T. Leininger2 — 1Physics Department, University of Newcastle upon Tyne, NEWCASTLE upon TYNE, NE1 7RU, UK — 2Laboratoire de Physique Quantique, UMR 5626 du CNRS, IRSAMC, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse Cedex 4, France
In order to assist the achievement of Bose-Einstein condensation of atomic hydrogen it has been proposed recently to use enhanced cooling by a cloud of ultracold lithium atoms [1]. The efficiency of this cooling is determined by the scattering length for triplet Li-H collisions. An improved ab initio calculation has been performed for the potential for the LiH a 3Σ+ state, using two very large basis sets. The BSSE correction has been determined for both basis sets and the non-Born-Oppenheimer correction estimated to be negligible. The best potential is approximately 10% deeper than the previous estimate. Vibrational energies and scattering lengths have been calculated for 6,7LiH(D) with both potentials, with and without the BSSE correction, and also with an estimated potential expected to bracket the true potential. While the low energy cross section in the best a 3Σ+ potential is about half that calculated previously [1], enhanced cooling by 7Li of trapped H atoms remains feasible.
[1] R. Côté, M. J. Jamieson, Z.C. Yan, N. Geum, G. H. Jeung and A. Dalgarno, Phys. Rev. Lett. 84 2806 (2000)