A Molecular-Dynamics Study on Metal-Immersed Hydrogen Fluids

Abstract

This work is aimed at the interactions between hydrogen atoms contained in high concentrations in metal lattices. Effects of metals on hydrogen interactions are surveyed by carrying out molecular dynamics (MD) simulations on hydrogen fluids containing palladium atoms, from a viewpoint in contrast to previous simulations on low concentrations of hydrogen in metal lattices. Some results of these simulations reveal the dissociation of H2 molecules to H atoms due to the presence of Pd atoms under densification, and therefore imply the change of attractive H-H interactions in H2 molecules to repulsive interactions of H atoms in Pd lattices. These repulsive interactions are consistent with an empirical “2-Å rule” of hydrogen atoms in metal lattices, and impose limits on hydrogen-storage capacities of metals.