Split interstitials in an interacting bcc alloy. II. Transport coefficients

The transport coefficients are derived in a concentrated interacting body centered cubic alloy for diffusion with the dumbbell mechanism. We use the self-consistent mean field theory in both point and pair approximations on the basis of the first paper of the series, and present two independent approximations (first and second shell approximations) for the calculation of the corresponding correlation coefficients. Correlation coefficients and uncorrelated transport coefficients obtained by those approximations are compared with Monte Carlo simulations for different sets of interactions. In the specific case of a strong clustering tendency and/or strong dumbbell-atom interactions, good agreement with Monte Carlo simulations requires a statistical pair approximation for the uncorrelated transport coefficients and a second shell approximation for the correlation coefficients.