Gibbs-Duhem integration in lattice systems

F. A. Escobedo and J. J. de Pablo

Department of Chemical Engineering, University of Wisconsin-Madison
Madison, Wisconsin, 53706-1691, USA

(received 27 January 1997; accepted in final form 9 September 1997)

PACS. 02.70Lq - Monte Carlo and statistical methods.
PACS. 61.25Mv - Liquid metals and alloys.
PACS. 64.70Fx - Liquid-vapor transitions.

Abstract:

Gibbs-Duhem integrations are performed to trace the vapor-liquid coexistence curves of homopolymers on a lattice. The integration entails simultaneous grand canonical simulations for the two coexisting phases and, consequently, no pressure evaluations or volume moves are necessary. Since mechanical equilibration of lattice systems can be troublesome, the proposed method offers some advantages over alternative approaches for phase equilibrium simulation, such as the integration of Clapeyron's equation and the Gibbs ensemble. Simulation results are presented for homopolymers and block copolymers; good agreement is found with previous Gibbs-ensemble results for homopolymers.

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