Stuttgart 2012 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 13: Poster 1: Cold Molecules, Femtosecond Spectroscopy, Molecular Dynamics
MO 13.10: Poster
Dienstag, 13. März 2012, 16:30–19:00, Poster.IV
Systematic analysis of long-range interactions between vibrating polar bialkali molecules — Romain Vexiau, Maxence Lepers, Mireille Aymar, •Olivier Dulieu, and Nadia Bouloufa — laboratoire Aimé Cotton, CNRS, Université Paris-Sud, Orsay, France
The determination of the long-range anisotropic interactions between polar bialkali molecules is of crucial importance for the achievement of a quantum gas of ultracold polar molecules. In particular, the dispersion coefficient C6 of the van der Waals interaction depends on the dynamic polarizability of the molecule evaluated at imaginary frequencies, expressed as a sum over all possible radiative transitions of electronic dipole moments. Using a mixture of up-to-date spectroscopic data and accurate ab initio data for potential energy curves, and permanent and transition dipole moments, we have obtained the values of the dispersion coefficients between identical polar molecules (LiNa, LiK, LiRb, LiCs, NaK, NaRb, NaCs, KRb, KCs, RbCs) in an arbitrary vibrational level of their electronic ground state. A careful analysis of the importance of the various kinds of transitions contributing to the sum has been performed. The C6 values significantly decrease with increasing vibrational levels towards the sum of the C6 coefficients between the four involved atomic pairs. For the lowest vibrational levels the C6 parameter varies from about 104 atomic units for KRb up to 107 atomic units for NaCs, which will lead to different collisional regimes at ultracold temperatures.