Analysis of Photoassociation Spectra for Giant Helium Dimers.

J. Léonard (1) , A.P. Mosk (1) , M. Walhout (1) , P. van Der Straten (1) , M. Leduc (1) , C. Cohen-Tannoudji (1, 2)

1 LKB (Lhomond) - Laboratoire Kastler Brossel
2 LKB [Collège de France] - Laboratoire Kastler Brossel

We perform a theoretical analysis to interpret the spectra of purelylong-range helium dimers produced by photoassociation (PA) in anultra-cold gas of metastable helium atoms. The experimental spectrumobtained with the PA laser tuned closed to the $2^3S_1\leftrightarrow2^3P_0$ atomic line has been reported in a previous Letter. Here, wefirst focus on the corrections to be applied to the measured resonancefrequencies in order to infer the molecular binding energies. We thenpresent a calculation of the vibrational spectra for the purelylong-range molecular states, using adiabatic potentials obtained fromperturbation theory. With retardation effects taken into account, theagreement between experimental and theoretical determinations of thespectrum for the $0_u^+$ purely long-range potential well is very good.The results yield a determination of the lifetime of the $2^3P$ atomicstate.

Domaines: Physique Quantique [quant-ph]

J. Léonard, A.P. Mosk, M. Walhout, P. van Der Straten, M. Leduc, et al.. Analysis of Photoassociation Spectra for Giant Helium Dimers.. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2004, 69, pp.032702. ⟨hal-00000660⟩