DFT study of hydrogen instability and magnetovolume effects in CeNi

Changes in electronic and magnetic structure due to hydrogen uptake within CeNi leading to the experimental hydride CeNiH₃, are examined ab initio for identifying the hydrogen positions and establishing the equations of state. Analyses of the site projected density of states and of the chemical bonding point to modifications of the electronic structure whereby hydrogen brings new states within the valence band and is found to preferably bind with Ni rather than with Ce. From energy differences hydrogen binds weakly to the lattice, in agreement with the instability of the hydrided binary intermetallic.