\textit{Ab Initio }Studies of Si$_{m}$Ge$_{n }$(m+n $\leq$ 5) Nanoclusters

Electronic and geometric structure properties of Si$_{m}$Ge$_{n}$(m+n $\leq$ 5) nanoclusters have been investigated using hybrid density functional B3LYP, 6-311G (3df, 3pd) basis set, and the GAUSSIAN 03 software. For the Si atom, the computed values of the ionization potential and electron affinity are 8.11 and 1.10eV, and for the Ge atom, the values are 7.90 and 1.14eV. The experimental values are 8.15, 1.39, 7.90, and 1.23eV, respectively. Various possible geometries have been spin-optimized to determine the global minimum for each nanocluster. We will present the electronic and geometric structures of the isomers of each nanocluster, including bond length, symmetry group, electronic state, binding energy, HOMO-LUMO gap, ionization potential, and electron affinity. In addition, the harmonic frequencies, fragmentation energies, average coordination number and Mulliken atomic charges will also be discussed for the ground states of the nanoclusters.