Journal of Physics B19 (1986) L593-L599

Journal of Physics B19 (1986) L593-L599
Accurate wavenumbers of the first resonance doublet of francium
atomsand relativistic contribution to isotope shifts in the resonance
doublets of francium and caesium atoms
J. Bauche, H.T. Duong, P. Juncara, S. Liberman, J. Pinard,
Laboratoire Aimé-Cotton, CNRS II, Bâtiment 505, F-91405 Orsay
A. Coc, C. Thibault, F. Touchard,
Laboratoire René-Bernas du CSNSM, BP 1, F-91406 Orsay
J. Lermé, J.L. Vialle,
Laboratoire de Spectrométrie Ionique et Moléculaire, Université de Lyon I, F-69621
Villeurbanne Cedex
S. Büttgenbachb,
e Institut für Angewandte Physik, Universität Bonn, D-5300 Bonn
A.C. Mueller,
GANIL, BP 5027, F-14021 Caen Cedex
A. Pesnelle,
Service de Physique des Atomes et des Surfaces, CEN Saclay, F-91191 Gif-sur-Yvette Cedex
and the ISOLDE Collaboration
CERN, CH-1211 Genève 23
a Present address: INM, CNAM, 292 rue St-martin, F-75141, Paris cedex 03
b Present address: Forschunginstitut FFMU, Breitscheidstrasse 2b, D-7000 Stuttgart 1
The results of a new experiment using high-resolution Doppler-free laser spectroscopy are
reported. Firstly, the wave numbers of the D1 and D2 lines of Fr atoms have been accurately
measured: σ(D1) = 12 237.409 (2) cm-1 and σ(D2) = 13 923.998 (2) cm-1. Secondly, the
isotope shifts of the D1 and D2 lines have been compared for Fr and Cs atoms. The
contribution of the p1/2 electron to the volume shift has been measured relative to that of the
s1/2 electron as 4.75(25) × 10-2 for Fr and 1.4(3) × 10-2 for Cs. They are discussed in terms of
semi-empirical calculations as well as relativistic Dirac-Fock ones.
© 1986 The Institute of Physics