Geometries and energies of small Gen(n= 2–6) clusters: an ab initio molecular orbital study

Abstract

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_∞h, ³Σ^–_g), Ge₃(equilateral triangle, D_3h³A^′₂), Ge₄(planar rhombus D_2h¹A_g), Ge₅(oblate distorted trigonal bipyramid, D_3h¹A^′₁), Ge₆(edge-capped trigonal bipyramid, C_2v¹A₁).

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.