A simple dynamical criterion for crystallization of a colloidal fluid which undergoes Brownian motion is proposed, similar in spirit to the classic Lindemann melting rule. It states that the ratio of the long-time and short-time self-diffusion coefficients is a universal number very close to 0.1 along the freezing line. This phenomenological crystallization rule is confirmed both by Brownian dynamics simulations of a Yukawa liquid and by forced Rayleigh scattering experiments on charge-stabilized colloidal suspensions.

• Received 24 November 1992

DOI:https://doi.org/10.1103/PhysRevLett.70.1557