Structure and stability of aluminium doped lithiumclusters (LinAl0/+, n = 1–8): a case of the phenomenological shell model

Abstract

Quantum chemical calculations are performed on the aluminium doped lithium clusters Li_nAl at both neutral and cationic states using the DFT/B3LYP and CCSD(T) methods in conjugation with the aug-cc-pVaZ (a = D,T,Q) basis sets. The global minima are located and the growth mechanism is established. The electronic structure, geometrical parameters and energetic properties, such as average binding energy E_b, second difference of energy Δ²E, adiabatic and vertical ionization energy, and dissociated enthalpy, are evaluated using the coupled-cluster CCSD(T) method, whose energies are extrapolated to the complete basis set limit (CBS). The high stability of Li₅Al, Li₇Al, Li₆Al⁺ and Li₈Al⁺ that have the “magic numbers” of valence electrons, can be understood using the phenomenological shell model.