  Impurity diffusion coefficients are entirely obtained from a low cost
classical molecular statics technique (CMST). In particular, we show how CMST
is appropriate in order to describe the impurity diffusion behavior mediated by
a vacancy mechanism. In the context of the five-frequency model, CMST allows to
calculate all the microscopic parameters, namely: the free energy of vacancy
formation, the vacancy-solute binding energy and the involved jump frequencies,
from them, we obtain the macroscopic transport magnitudes such as: correlation
factor, solvent-enhancement factor, Onsager and diffusion coefficients.
Specifically, we perform our calculations in f.c.c. diluted Ni-Al and Al-U
alloys. Results for the tracer diffusion coefficients of solvent and solute
species are in agreement with available experimental data for both systems. We
conclude that in Ni-Al and Al-U systems solute atoms migrate by direct
interchange with vacancies in all the temperature range where there are
available experimental data. In the Al-U case, a vacancy drag mechanism could
occur at temperatures below 550K.
