Structure and Stability of GeAun, n=1-10 clusters: A Density Functional Study

The structures of Germanium doped gold clusters GeAun (n=1-10) have been investigated using ab initio calculations based on density functional theory (DFT). We have obtained ground state geometries of GeAun clusters and have it compared with Silicon doped gold clusters and pure gold clusters. The ground state geometries of the GeAun clusters show patterns similar to silicon doped gold clusters except for n = 5, 6 and 9. The introduction of germanium atom increases the binding energy of gold clusters. The binding energy per atom of germanium doped cluster is smaller than the corresponding silicon doped gold cluster. The HUMO-LOMO gap for Au-n Ge clusters have been found to vary between 0.46 eV - 2.09 eV. The mullikan charge analysis indicates that charge of order of 0.1e always transfers from germanium atom to gold atom