Configuration-independent elastic interactions in metal-hydrogen solutions

Abstract. We demonstrate quantitative methods for estimating that part of the elastic interaction energy between defects in solids which does not depend on the precise spatial arrangement of the defects. This energy involves both the total volume change per defect in the finite solid and the purely shear part of the volume change. Several different continuum and atomistic modelling methods are used to calculate these volume changes for H in Pd. V, Nb and Ta. An estimate of the configuration-independent elastic interaction energy is made for the Pd-H system as a function of the H concentration, and is given in a form suitable for comparison with statistical models. 1