Abstract: The universal-parameter nonorthogonal tight-binding scheme proposed by Menon and Subbaswamy was used to optimize the geometrical structures, binding energies and electron affinities of small germanium clusters Ge_n (n =2—20). A complete agreement with available ab initio results from the lowest energy structures for Ge₂—Ge₆ was obtained and reasonable structures for these clusters were predicted and compared with those of corresponding silicon clusters in the range of n =7—20. The averaged discrepancy with experiments in binding energies for n =2—7 is about 6% and the calculated electron affinities agree well with the measured values in the range of n =2—8 as well.

Key words: Germanium cluster, Tight-binding study, Geometry, Electronic property