  In this work we perform a comparison between Classical Molecular Static (CMS)
and quantum Density Functional Theory (DFT) calculations in order to obtain the
diffusion coefficients for diluted \emph{Fe-Cr} alloys. We show that, in
accordance with Bohr's correspondence principle, as the size of the atomic cell
(total number of atoms) is increased, quantum results with DFT approach to the
classical ones obtained with CMS. Quantum coherence effects play a crucial role
in the difference arising between CMS and DFT calculations. Also, thermal
contact with the environment destroys quantum coherent effects making the
classical behavior to emerge. Indeed, CMS calculations are in good agreement
with available experimental data. We claim that, the atomic diffusion process
in metals is a classical phenomena. Then, if reliable semi empirical potentials
are available, a classical treatment of the atomic transport in metals is much
convenient than DFT.
