Search for the Lin(0/+1/-1) (n = 5-7) Lowest-Energy Structures Using the ab Initio Gradient Embedded Genetic Algorithm (GEGA). Elucidation of the Chemical Bonding in the Lithium Clusters.

We report the study of small lithium clusters Lin(0/+1/)(-)(1) (n = 5-7), performed via the novel Gradient Embedded Genetic Algorithm (GEGA) technique and molecular orbital analysis. GEGA was developed for searching of the lowest-energy structures of clusters. Results of our search, obtained using this program, have been compared with the previous ab initio calculations, and the efficiency of the developed GEGA method has thus been confirmed. The molecular orbital analysis of the found Lin(0/+1/)(-)(1) (n = 5-7) clusters showed the presence of multiple (σ and π) aromatic character in their chemical bonding, which governs their preferable shapes and special stability.