Alkalization of aluminum clusters

Equilibrium geometries, binding energies, ionization potentials, and electron affinities of neutral and charged Al-n clusters (n less than or equal to 8) decorated with alkali atoms such as Li and K have been calculated using molecular orbital theory based on density functional formalism and generalized gradient approximation. While the electron affinities and the ionization potentials depend on size, no clear signatures of shell closings are found in this size range. Similar studies on Al5Xm (X=Li, K, 1 less than or equal to m less than or equal to 4) also fail to provide any indication consistent with shell closings. On the other hand, the ionization potentials and electron affinities of aluminum clusters decrease with the addition of alkali atoms. The results are in good agreement with available experimental data. (C) 2000 American Institute of Physics. [S0021-9606(00)30728-0].