First-principles investigations of the stability and electronic structure of ZrV2Hx (x=0.5, 1, 2, 3, 4, 6 and 7) Original Research Article

A calculation of the electronic structure and formation energy for ZrV2Hx (x=0.5, 1, 2, 3, 4, 6 and 7) is performed using a plane-wave pseudo-potential method. It is found that in ZrV2Hx hydrogen forms stronger covalent bonds with vanadium than with zirconium if Zr atoms are in the neighborhood of V. A detailed analysis of how the densities of states change with the hydrogen count x in ZrV2Hx shows the changes in the bonding and anti-bonding interactions of H with V and Zr. However, the covalent anti-bonding interactions between H and V seem to be mainly responsible for the variation in the formation energy of ZrV2Hx with x. The value of projected density of states of V 3d at the Fermi level can be used as a rough comparative measure for these anti-bonding interactions and therefore allows us to predict the changes in stability of ZrV2Hx with x.