Silicon–sodium binary clusters Si nNa ( n ⩽ 10) and their anions: Structures, thermochemistry, and electron affinities

Abstract

The molecular structures, electron affinities, and dissociation energies of the Si n Na/Si n Na − ( n ⩽ 10) species have been investigated by means of five hybrid and pure density functional theory (DFT) methods. The basis sets used in this work is of double- ζ plus polarization quality with additional diffuse functions, denoted DZP++. The geometries are fully optimized with each DFT method independently. Three different types of the neutral-anion 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). Compared with the limited experimental values of EA ad and VDE, the BPW91 and B3PW91 scheme provided the most reliable EA ad and VDE values. The dissociation energy D e (Si n Na → Si n +Na) for the neutral Si n Na and D e ( Si n Na - → Si n - + Na ) for the anionic Si n Na − species have also been reported and used to understand relative stability.