Core electron level shifts in zirconium induced by vacancy, helium and hydrogen

The paper presents a first-principle calculation of the influence of lattice defects (a hydrogen atom, a vacancy and a helium-in-vacancy complex) and their concentration on the core electron binding energies in zirconium atoms. It is shown that the formation of a vacancy or a helium-in-vacancy complex causes core-level shifts of Zr atoms to lower binding energies. Hydrogen dissolution leads to core-level shifts to both lower and higher binding energies. Besides, the effects of electron density redistribution in zirconium (due to the appearance of the defect and, as a consequence, the change of the crystal volume and the lattice relaxation around the defect) on the core electron binding energies are studied.