Binding of helium to metallic impurities in tungsten. Experiments and computer simulations

A W(100) single crystal was implanted with low doses Ag, Cu, Mn, Cr, Al or In. Subsequent heating to 1600 K removed all vacancies and left the implants in substitutional positions. Low energy He was injected, and binding of He to the substitutional impurities was observed. Binding energies were found as high as 1.25 eV for one He atom. Pair potential calculations were performed; the calculated binding energies correspond reasonably with the measured ones. (orig.)