Despite recent advances, precise simulation of freezing transitions remains a challenging task. In this work, a simulation method for fluid-solid transitions, based on a modification of the constrained cell model of Hoover and Ree, is developed. In the constrained cell model, each particle is confined within its own Wigner-Seitz cell. The constrained cell model is a limiting case of a more general or modified cell model which is constructed by adding an external field that controls the relative stability of the two phases. Constant-pressure simulations of the modified cell model indicate that the transition from the fluid to the solid is continuous at low and moderate pressures and discontinuous at high pressures. The special point that separates continuous from discontinuous behavior is very close to the mechanical stability point of the solid phase. The fluid-solid transition of model systems has been determined either by analyzing the filed-induced phase transition of the corresponding modified cell model or via thermodynamic integration based on the same model. The size-dependent coexistence pressures and densities have been analyzed according to finite-size scaling techniques for first-order phase transitions. The results clearly demonstrate the importance of accounting for size effects in simulation studies of fluid-solid transitions.
Journal: TechConnect Briefs
Volume: 2, Nanotechnology 2012: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational (Volume 2)
Published: June 18, 2012
Pages: 708 - 711
Industry sector: Advanced Materials & Manufacturing
Topic: Informatics, Modeling & Simulation