Evolution of geometrical structures, stabilities and electronic properties of neutral and anionic Li_ n Cu~ λ (n = 1-9, λ = 0,-1) clusters: Compare with pure lithium clusters

摘要

The structural evolution, stabilities, and electronic properties of copper-doped lithium Li_ n Cu~λ (n = 1-9, λ = 0,-1) clusters have been systematically investigated using a density functional method at PW91PW91 level. Extensive searches for ground-state structures were carried out, and the results showed the copper tends to occupy the most highly coordinated position and form the largest probable number of bonds with lithium atoms. By calculating the binding energies per atom, fragmentation energies and the HOMO-LOMO gaps, we found LiCu, Li_7Cu, LiCu~-, Li_ 2Cu~- and Li_8Cu~- clusters have the stronger relative stability and enhanced chemical stability. The content and pattern of frontier MOs for the most stable doped isomers were analysed to investigate the bond nature of interaction among Li and Cu atoms. The results show some σ-type and π-type bonds are formed among them, and with small admixture of the Cu d characters. To achieve a deep insight into the electron localization and reliable electronic structure information, the natural population analysis and electron localization function were performed and discussed.