Theoretical studies of the global minima and polarizabilities of small lithium clusters

Highlights: Theoretical searching of the global minima structures of Li_1-20 clusters. State-of-the-art calculation of the polarizabilities (α) of Li_1-20 clusters. A linear correlation investigation of the inverse relationship between α and IP. Thermal effect investigation of the discrepancy between measured and computed α. Lithium clusters Li_n (n = 1-20) have been investigated with density functional theory (DFT) and coupled-cluster (CC) methods. The global minima are located via an improved basin-hopping algorithm. Simulated polarizabilities are in good agreement with the measured data generally. The simulated polarizabilities for Li₆, Li₁₂ and Li₁₉ are in reasonable agreement when thermal effects are included, except the Li₃ cluster. A linear correlation for the inverse relationship between the CCSD calculated polarizabilities and ionization potential (IP) has been reported to have the linear coefficient of 0.996, which further strengthens our simulations.