Eur. Phys. J. D 57, 171-177 (2010)
https://doi.org/10.1140/epjd/e2010-00058-y

The ¹S+¹S asymptote of Sr₂ studied by Fourier-transform spectroscopy ^*

Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany

Corresponding author: stein@iqo.uni-hannover.de

Received: 21 January 2010
Published online: 9 March 2010

Abstract

An experimental study of the long range behavior of the ground state X¹Σ⁺_g of Sr₂ is performed by high resolution spectroscopy of asymptotic vibrational levels and the use of available photoassociation data. Ground state levels as high as v''=60 (outer turning point at 23 Å and 0.1 cm^-1 below the asymptote) could be observed by Fourier-transform spectroscopy of fluorescence progressions induced by single frequency laser excitation of the v'=4, J'=9 rovibrational level of the state 2¹Σ⁺_u. A precise value of the scattering length for the isotopologue ⁸⁸Sr₂ is derived and transferred to all other isotopic combinations by mass scaling with the given potential. The derived potential together with already published information about the state 2¹Σ⁺_u directs to promising optical paths for producing cold molecules in the electronic ground state from an ultracold ensemble of Sr atoms.