The solution of inert gas atoms in metals

Abstract

Abstract Estimates are made of the energies of interstitial and substitutional solutions of inert gas atoms in a simple metal. The loss of cohesion round such an atom is taken into account by regarding the atom as occupying a vacancy in the metal. Most of the energy of solution, particularly for the larger atoms, originates from the closed-shell interactions, which are estimated from interaction potentials based on data for the inert gases and on Huntington's potential for copper ions. Argon, krypton and xenon are expected to dissolve substitutionally in copper under all circumstances, even to the extent of forcing copper atoms off the lattice if no vacant sites are available. Neon should and helium may dissolve substitutionally when vacancies are available, but not otherwise. The strains round xenon and krypton atoms are so large that extra vacancies may be captured by these atoms to reduce the strain energy. The solubilities and diffusion of inert gas atoms in metals are briefly discussed in the light of these conclusions.