Structural and Electronic Properties of (HfH2)n (n=5-30) Clusters: Theoretical Investigation

Metallic hydride clusters have greater importance due to its unique physicomechanical properties. For solid-state hydrogen storage, (HfH2)(n) clusters has been considered a promising candidate because of high hydrogen capacity, low cost and larger interacting affinity between atoms. The structural and electronic properties of (HfH2)(n), clusters are investigated by employing the density functional theory. From the DFT calculations, it is found that Hf atom occupies central position while H atoms tends to occupy at vertex spots. Through structural stability analysis, the calculated binding energy and second order energy difference of (HfH2)(n) clusters increases from (HfH2)(5) through (HfH2)(30). The charge density distribution and results of Bader analysis revealed ionic bonding character between Hf and H atoms and transfer of electrons is observed from Hf to H atoms. The orbital overlapping contribution of the interacting Hf and H atom is also performed.