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MO: Fachverband Molekülphysik

MO 4: Cold Molecules I

MO 4.3: Vortrag

Montag, 12. März 2012, 14:30–14:45, V38.03

Long-range interactions in cold atomic and molecular samples — Maxence Lepers¹, Romain Vexiau¹, Mireille Aymar¹, Béatrice Bussery-Honvault², Jean-François Wyart¹, Nadia Bouloufa¹, and •Olivier Dulieu¹ — ¹laboratoire Aimé Cotton, CNRS, Université Paris-Sud, Orsay, France — ²Laboratoire Interdisciplinaire Carnot de Bourgogne, Université de Bourgogne, Dijon, France

Long-range interactions play a crucial role in cold and ultracold physics and chemistry, for example on elastic, inelastic and reactive collisions between atoms and molecules. In this work, we have characterized the long-range interactions for a wide variety of systems being of strong experimental interest. We have calculated the asymptotic electrostatic interaction energy between alkali-metal atoms and diatomic molecules, between erbium atoms, and between oxygen atoms and molecules. In particular, we have focused our study on the Van der Waals contribution which requires a detailed knowledge of the energy spectrum of the two interacting partners. Improved values of dynamic polarizabilities based on accurate ab initio calculations as well as on up-to-date spectroscopic analysis have been determined.

We have obtained a huge dispersion in the Van der Waals coefficients, ranging from a few tens of atomic units for O+O₂, to a few 10⁵ atomic units for polar diatomic molecules in their ground rovibrational level. In the atom-diatom case, we have shown that for sufficiently small distances the rotational levels of the diatomic molecule can be coupled due to the presence of the partner, leading to a complex pattern of potential energy curves, and possibly a complex collisional dynamics.