Probing the electronic structures and properties of neutral and charged CaSin- (n=2-10) clusters using Gaussian-3 theory

The structures and energies of small CaSin (n = 2-10) species and their anions have been systematically investigated by means of the Gaussian-3 (G3) theory. The electron affinities have been presented and compared with those of MgSin and BeSin. The ground state structures for all of these species are found to be "substitutional structure", which are derived from Sin+1 by replacing a Si atom with a Ca atom. The reliable adiabatic electron affinities of CaSin have been predicted to be 1.56 eV for CaSi2, 1.77 eV for CaSi3, 2.01 eV for CaSi4, 2.06 eV for CaSi5, 1.97 eV for CaSi6, 1.98 eV for CaSi7, 1.86 eV for CaSi8, 2.49 eV for CaSi9, and 2.32 eV for CaSi10. The dissociation energies of Ca atom from the lowest energy structure of CaSin clusters have been calculated in order to examine relative stabilities. Compared with those of BeSin and MgSin, the dissociation energies of Mg from MgSin are the smallest. The charge transfer of CaSin and BeSin has also been computed to further understand the interaction between the metal atom and the silicon clusters. (C) 2011 Elsevier B.V. All rights reserved.