ABSTRACT:The hydrogenated silicon clusters structures, electron affinities, and dissociation energies of the Si 6 H n /Si 6 H n Ϫ (n ϭ 3Ϫ14) species have been systematically investigated by means of three density functional theory (DFT) methods. The basis set used in this work is of double-plus polarization quality with additional diffuse s-and p-type functions, denoted DZPϩϩ. The geometries are fully optimized with each DFT method independently. Three different types of energy separations presented in this work are the adiabatic electron affinity (EA ad ), the vertical electron affinity (EA vert ), and the vertical detachment energy (VDE). The first SiOH dissociation energies D e (Si 6 H n 3 Si 6 H n-1 ϩH) for the neutral Si 6 H n and D e (Si 6 H n Ϫ 3 Si 6 H nϪ1 Ϫ ϩH) for the anionic Si 6 H n Ϫ species have also been reported.