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

Abstract

Quantum chemical calculations are performed on the aluminium doped lithium clusters Li(n)Al 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 Δ(2)E, 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 Li(5)Al, Li(7)Al, Li(6)Al(+) and Li(8)Al(+) that have the "magic numbers" of valence electrons, can be understood using the phenomenological shell model.