Alkali metal doped nickel oxide clusters: A density functional study

The results of density functional theory based calculations on alkali metal doped nickel oxide clusters, MNi n O m (M = Li, Na, K) with n = 1, 2 and m = 1–4 are reported here. A preference for planar arrangement of the constituent atoms maximizing the ionic interactions is found in the ground state of the clusters considered except for MNi 2 O cluster. In presence of alkali metal atom, the sequential oxidation of the metal-excess cluster increases the charge transfer from Ni to O atoms which results in increase in binding energy. The enhanced stability is found in case of Li doped nickel oxide clusters. The spin state of these clusters depend upon Ni–O as well as O–O interactions. The increase in the oxygen to metal ratio in these clusters is accompanied by increase in both electron affinity and ionization potential. Stability, magnetic behavior, and nature of bonding is further explained on the basis of total and projected density of states on Ni, O, and M atoms.