# Photo-association de l'hélium métastable au voisinage de la Condensation de Bose-Einstein et formation de dimères géants

Abstract : In the vicinity of Bose-Einstein condensation, the collisional
properties of a dilute gas of metastable helium (He $2^3S$) are
governed by the rate of ionizing Penning collisions and the s-wave
scattering length. In order to investigate these properties, we have carried out new photoassociation experiments in which a pair of free atoms absorbs a photon to produce a molecule in an excited electronic state. In particular, we have observed giant dimers" for which the autoionizing process is inhibited. Accurate spectra have been acquired by the use of an original `calorimetric" detection scheme. In addition, we have calculated long-range electronic potentials for the $2^3S+2^3P$ system. Our asymptotic approach is described in detail, which reproduces the measured binding energies of the giant dimers with
very good accuracy.
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Cited literature [117 references]

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Submitted on : Friday, January 23, 2004 - 1:39:15 PM
Last modification on : Thursday, March 17, 2022 - 10:08:06 AM
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• HAL Id : tel-00004295, version 1

### Citation

Jérémie Léonard. Photo-association de l'hélium métastable au voisinage de la Condensation de Bose-Einstein et formation de dimères géants. Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2003. Français. ⟨tel-00004295⟩

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