THE INFLUENCE OF THE RELATIVE DENSITY OF A SOLUTE PARTICLE ON THE MEMORY FUNCTION

The effect of mass and size on the self-diffusion of a Brownian partic le in a (T, p, N) ensemble is studied in a two-dimensional Lennard-Jon es fluid through the Mori coefficients. A generalization of the Toxvae rd expression for the first Mori coefficient was found as a consequenc e of the effect of changing the solute particle's volume. The analysis of the effect of volume on the self-diffusion shows two different typ es of behaviour depending on whether the Brownian particle has the sam e mass as the environment particles or not.