https://doi.org/10.1007/s100530050303
Simple determination of Na2 scattering lengths using observed bound levels at the ground state asymptote
1
Laboratoire Aimé Cotton, CNRS II, bât. 505, Campus
d'Orsay, 91405 Orsay, France
2
Institut für Quantenoptik, Universität Hannover, 30167 Hannover, Germany
Received:
28
September
1998
Revised:
21
December
1998
Published online: 15 May 1999
A simple model is developed to determine a scattering length from the
experimental values of the energy of the last, least bound, vibrational
levels of the ground state, either or
,
of an alkali dimer. It is based on an extrapolation of the positions of the
few outermost nodes of the bound vibrational wave functions towards the
dissociation threshold. It uses the asymptotic part of the molecular
potential only. The method is applied to recently measured levels at the
asymptote (3s+3s) of Na2. We obtain precise values for the two scattering
lengths respectively associated to the dissociation limits
(55.1±1.6 a0) and
(50.0±1.6 a0); the first
value corresponds to the
scattering length usually considered in
cold collisions. The extrapolation procedure is also applied to Li2,
using existing experimental data.
PACS: 33.20.Kf – Visible spectra / 32.80.Pj – Optical cooling of atoms; trapping / 34.50.Pi – State-to-state scattering analyses
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999