Geometries, stabilities and electronic properties of beryllium-silicon Be₂Si(n) clusters

The equilibrium geometries, growth patterns, stabilities, and electronic properties of bimetallic Be₂Si(n) (n = 1-11) clusters are systematically investigated at the B3LYP/6-311G(d) level of theory. Harmonic vibrational analysis has been performed to assure that the optimized geometries are stable. The optimized results suggest that the three-dimensional structures are observed for the most stable isomers of Be₂Si(n) clusters when n > 2. The calculated vertical ionization potential for the lowest-energy isomers are comparable to the experimental values of Si(n+2). According to the averaged binding energy, fragmentation energy, second-order energy difference and HOMO-LUMO gaps calculations, we identify that the Be₂Si₂ and Be₂Si₅ clusters are more stable, and Be atoms doping enhance the chemical reactivity of the Si n host. The natural population and natural electron configuration analyses indicate that the Be atoms possess positive charge at n = 1-5 but negative charge at n = 6-11. The chemical hardness of Be₂Si(n) clusters show three local maxima at n = 2, 5, and 9, whereas three local minima are found for the corresponding chemical potential, meaning these clusters are more stable than their neighboring cluster sizes.