We show that the kinetic-theoretical self-diffusion coefficient of an atomic fluid plays the same role as the short-time self-diffusion coefficient D_S in a colloidal liquid, in the sense that the dynamic properties of the former, at times much longer than the mean free time, and properly scaled with D_S, will indistinguishable from those of a colloidal liquid with the same interaction potential. One important consequence of such dynamic equivalence is that the ratio D_L/ D_S of the long-time to the short-time self-diffusion coefficients must then be the same for both, an atomic and a colloidal system characterized by the same inter-particle interactions. This naturally extends to atomic fluids a well-known dynamic criterion for freezing of colloidal liquids[Phys. Rev. Lett. 70, 1557 (1993)]. We corroborate these predictions by comparing molecular and Brownian dynamics simulations on (soft- and hard-sphere) model systems, representative of what we may refer to as the "hard-sphere" dynamic universality class.
@article{arxiv.1106.2475,
title = {Dynamic equivalence between atomic and colloidal liquids},
author = {Leticia López-Flores and Patricia Mendoza-Méndez and Luis E. Sánchez-Díaz and Gabriel Pérez-Ángel and Martín Chávez-Páez and Alejandro Vizcarra-Rendón and Magdaleno Medina-Noyola},
journal= {arXiv preprint arXiv:1106.2475},
year = {2015}
}