Simulation of nucleation in almost hard-sphere colloids: the discrepancy between experiment and simulation persists

Area of Science:

• Computational physics
• Materials science
• Chemical physics

Background:

• The Weeks-Chandler-Andersen (WCA) potential is a fundamental model in statistical mechanics.
• Previous studies on WCA crystal nucleation reported agreement with experimental data, contradicting earlier simulations.

Purpose of the Study:

• To re-examine the phase behavior and crystal nucleation rates of the WCA potential.
• To resolve discrepancies in reported nucleation rates between simulations and experiments.

Main Methods:

• Extensive numerical simulations using Brownian dynamics, umbrella sampling, and forward flux sampling.
• Comparison of simulation results with hard-sphere models.

Main Results:

• All employed simulation techniques yielded consistent nucleation rates.
• The computed nucleation rates significantly differ from those reported by Kawasaki and Tanaka.
• Mapping the WCA model to a hard-sphere system showed good agreement with prior hard-sphere simulations.

Conclusions:

• The discrepancy between simulated and experimental crystal nucleation rates for the WCA potential persists.
• The findings suggest that earlier claims of agreement between simulation and experiment were likely inaccurate.