Eur. Phys. J. D 2, 63-73 (1998)
https://doi.org/10.1007/s100530050112

Predictions of geometrical structures and ionization potentials for small barium clusters Ba_n

¹ Laboratoire de Spectrométrie Ionique et Moléculaire ( UMR 5579 du CNRS) , Université Claude Bernard Lyon I, Bâtiment 205, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne Cedex, France
² Laboratoire de Physique Quantique (UMR 5626 du CNRS) , IRSAMC, Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex, France

Corresponding author: ^a frecon@in2p3.fr

Received: 14 May 1997
Revised: 2 February 1998
Accepted: 27 February 1998
Published online: 15 April 1998

Abstract

The geometrical structure of ground state Ba_n clusters () has been predicted from various types of calculations including two ab initio approaches used for the smaller sizes namely HF+MP2), DFT (LSDA), 9) and one model approach HF+pairwise dispersion used for all sizes investigated here. The lowest energy configurations as well as some isomers have been investigated. The sizes n=4, 7 and 13 are predicted to be the relatively more stable ones and they correspond to the three compact structures: the tetrahedron, the pentagonal bipyramid and the icosahedron. The growth behavior from Ba₇ to Ba₁₃ appears to be characterized by the addition of atoms around a pentagonal bipyramid leading to the icosahedral structure of Ba₁₃ which is consistent with the observed size-distribution of barium clusters. Values for vertical ionization potentials calculated for at the CI level are seen to be in quite good agreement with recent measures.