Analysis and assessment of the structural, electronic properties of (ZrH2)n (n = 5–24) clusters: Density function theory calculations

Abstract

Initial structures generated by artificial bee colony algorithm were re-optimized, and structural and electronic properties for (ZrH2)n (n = 5–24) were calculated using density functional theory. Zr atoms of (ZrH2)n clusters, tend to occupy the edge positions, whereas the majority of H atoms dissociate to the vertex sites. The formation energies increase from (ZrH2)5 through (ZrH2)21 clusters, showing increased stability. Zr 4d, 5s and H 1s orbitals overlap over a wide range, showing stronger chemical bonding, which increases with increasing cluster size. Cluster (ZrH2)21, is the most stable cluster, with the least formation energy −7.278 eV, and stronger ZrH chemical bonding. It is observed that ionic bonding exists between ZrH atoms of (ZrH2)n clusters. By the analysis of Bader charge and charge density difference, we came across the fact that charges transfer from Zr to H atoms. Also, the bond strengths for the maximal and minimal of structures, (ZrH2)5 and (ZrH2)11 clusters, were analyzed.