GEOMETRIES AND ENERGIES OF SMALL GEN (N = 2-6) CLUSTERS - AN AB-INITIO MOLECULAR-ORBITAL STUDY

The molecular geometries and relative stabilities of various electronic configurations of Ge(n) clusters (n = 2-6) have been investigated by means of ab initio calculations by employing an effective core potential for core electrons and a double zeta plus polarization functions basis set for valence electrons. The calculations have produced the following optimal configurations: Ge2 (D(infinity h), 3SIGMA(g)-), Ge3 (equilateral triangle, D3h 3A2'), Ge4 (planar rhombus D2h 1A(g)), Ge5 (oblate distorted trigonal bipyramid, D3h 1A1'), Ge6 (edge-capped trigonal bipyramid, C2v 1A1). Binding energies have been evaluated by single-point CISD(Q) calculations at the SCF optimal ground-state geometry of the clusters. The results are in qualitative agreement with experimental data. The comparison of Ge(n) and Si(n) properties shows close similarity between Ge and Si.