First Principles Study of Stability and Electronic Structure οf TMH and $TMH_2$ (TM = Y, Zr, Nb)

First principles calculations are performed by using Vienna ab initio simulation package within the framework of density functional theory to understand the electronic and structural properties of yttrium, zirconium and niobium hydrides. The equilibrium lattice constant, the bulk modulus, the total density of states and charge density distribution are analyzed in comparison with the available experimental and theoretical data. The X-ray diffraction pattern is also simulated to estimate the lattice constants of these hydrides. The formation energies are computed for rock-salt and fluorite structures using density functional theory. The calculated elastic constants obey the necessary stability conditions. A detailed analysis of the changes in density of states and electron density upon hydride formation has allowed us to understand the formation of these hydrides.