  Much effort has been put into developing theories for dense fluids, as a
result of these efforts many theories work for a certain type of particle or in
a certain concentration regime. Rosenfeld proposed a dependence of the
self-diffusion coefficient on the excess entropy. Our proposal is similar to
Rosenfeld's in that it also attempts to describe diffusion in terms of a
thermodynamic function but, instead of the excess entropy, we use the
thermodynamic factor, or the excess chemical potential. Simulations were taken
for hard spheres and our model was fitted with two free parameters. Simulations
were then carried out for a Lennard Jones gas and our model correctly described
the new data with the value of the free parameters that we had obtained for
hard spheres. This is a feature of our model that we wish to emphasize, since
the usual situation is that parameters have to be re-adjusted for different
interaction potentials. An experimental xenon self-diffusion data set was used
as an example where the model can be applied, especially in the high-density
regime.
