Predictions of geometrical structures and ionization potentials for small barium clusters Ban V. Boutou, A. R. Allouche, F. Spiegelmann, J. Chevaleyre and M. Aubert Frécon Eur. Phys. J. D, 2 1 (1998) 63-73 Published online: 15 April 1998 DOI: 10.1007/s100530050112