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The European Physical Journal D

, Volume 57, Issue 2, pp 171-177

First online:

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

  • A. SteinAffiliated withInstitut für Quantenoptik, Leibniz Universität Hannover Email author 
  • , H. KnöckelAffiliated withInstitut für Quantenoptik, Leibniz Universität Hannover
  • , E. TiemannAffiliated withInstitut für Quantenoptik, Leibniz Universität Hannover

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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.