Structural and electronic properties of boron-doped lithium clusters: Ab initio and DFT studies

The lowest-energy structures and electronic properties of the BLin (n = 1-7) clusters are reported using the B3LYP, MP2, and CCSD(T) methods with the aug-cc-pVDZ basis set. Though the results at the B3LYP level agree well with those at the CCSD(T) level, the MP2 method is rather unsatisfactory. The first three-dimensional ground state in the BLin clusters occurs for BLi4, and the impurity B atom is seen to be trapped in a Li cage from the BLi6 cluster onwards. The evolution of the binding energies, vertical ionization potentials, and polarizability with size of cluster shows the BLi5 cluster to be most stable among the BLin clusters. Besides, the BLi5 cluster is also found to have the largest reaction enthalpy (49.8 kcal/mol) upon losing a Li atom, which is different from the previous prediction. The unique stability of the 8-valence electron BLi5 can be understood from the cluster electronic shell model (CSM). However, in contradiction to the prediction of the CSM, the 2s level is filled prior to the Id level in the BLin clusters. (C) 2007 Wiley Periodicals, Inc.