Abstract
Employing a time-dependent Ising model of the kind used in the preceding works of this series, we have studied the self-diffusion constant. In the local-equilibrium approximation, the self-diffusion constant is expressed in terms of certain equal-time spin correlation functions. At the critical point the self-diffusion constant is shown to have a finite value, and it is conjectured that it may have an infinite slope as a function of temperature at the critical point. The two relevant experiments are discussed.