DYNAMIC SCALING IN AN AGGREGATING 2D LENNARD-JONES SYSTEM

The evolution of a 2D Lennard-Jones system, quenched from the fluid to below the triple point, is simulated by molecular dynamics. We show that the structure factor obeys the scaling relation S(q/qm(t))∼qm(t)-dfS(q/qm). Here qm is the location of the low angle peak in S(q), df=1.85±0.05 is a fractal dimension, and S(q/qm) is a time-independent characteristic function which peaks at qm. The quenching process is thermodynamically similar to the formation of a gel from a sol. Hence the relation suggests that a characteristic fractal dimension of even a dense gel can be derived from measurements of the time evolution of S(q). © 1995 The American Physical Society.