Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)
A 12.39: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT3
Multichannel asymptotic model for the determination of scattering lengths from observed bound levels at ground state asymptotes of alkali dimers — •Benoit T’Jampens and Anne Crubellier — Laboratoire Aimé Cotton, CNRSII, bât. 505, Campus d’Orsay, F-91405 Orsay Cedex
Scattering lengths can be determined from observed bound levels close to the asymptote by a very simple method [1]. The key of the method is to obtain, by computation in the asymptotic zone only, the lines connecting the nodes of successive wavefunctions. These nodal lines are then extrapolated up to the threshold, yielding the positions of the nodes of the threshold wavefunction, which in turn yield a value of the scattering length.
The method has now been extended to the multichannel case. For the ground states of alkali dimers, the coupling is fully located in the asymptotic region. Knowledge of the inner part of the potential can thus be replaced by knowledge of the nodal lines located at the inner side of the coupling zone. In practice, two particular nodal lines (one triplet and one singlet), which are nearly straight lines in the near-threshold region, are used as fitting parameters. Application to the analysis of the energies of bound levels of Cs2 close to the 6s+6s asymptotes, recently measured by two-color spectroscopy, will be described.
[1] A. Crubellier, O. Dulieu, F. Masnou-Seeuws, M. Elbs, H. Knöckel, E. Tiemann, Eur. Phys. J. D 6, 211 (1999)