  We present a systematic study of the self-diffusion coefficient for a fluid
of particles interacting via the square-well pair potential by means of
molecular dynamics simulations in the canonical (N,V,T) ensemble. The discrete
nature of the interaction potential is modeled through the constant force
approximation and the self-diffusion coefficients is determined for several
packing fractions at super critical thermodynamic states. The dependence of the
self-diffusion coefficient with the potential range $\lambda$ is analyzed in
the range of $1.1 \leq \lambda \leq 1.5 $. The obtained molecular dynamics
simulations results are in agreement with the self-diffusion coefficient
predicted with the Enskog method. Additionally, we soh that the diffusion
coefficient is very sensitive to the potential range, $\lambda$, at low
densities leading to a density dependence of this coefficient not shared with
other macroscopic properties such as the equation of state. The constant force
approximation used in this work to model the discrete pair potential has shown
to be an excellent scheme to compute the transport properties using standar
computer simulations. Finally, the simulation results presented here are
resourceful to improving theoretical approaches, such as the Enskog method.
