Calculated energies and geometries for hydrogen impurities in Al and Mg

Abstract
Self-consistent jellium calculations of the electron structure of hydrogen in Al and Mg have been supplemented with a first-order calculation of the energy contribution of the pseudopotential lattice. It is found that the most stable interstitial position of hydrogen in both Al and Mg is the tetrahedral one, with heats of solution of 1.3 eV and -0.1 eV respectively. Within vacancies, the hydrogen is predicted to prefer off-centre positions with vacancy trapping energies of about 1 eV for Al and 0.1 eV for Mg. The results are compared with available experimental data and good agreement is found.