Filomena F. M. Freitas

The starting state in simulations of the fluid-solid coexistence by Gibbs-Duhem integration

A direct method to determine the starting state in simulations of the fluid–solid coexistence by Gibbs–Duhem integration is presented. It is based on the limiting behavior of the Gibbs Ensemble vapor–liquid calculations at the lowest temperature range. The approach estimates the location of the triple point and, from there up, the fluid–solid coexistence properties, at higher temperatures, are calculated by Gibbs–Duhem simulations. The technique is illustrated by tracing the phase diagram of the Lennard–Jones system. The usefulness of the method is discussed in view of our recent study on the phase behavior of C60 [Int. J. Quantum Chem. 84 (2001) 375].  2001 Elsevier Science B.V. All rights reserved.

A time saving algorithm for the Monte Carlo method of Metropolis

A time saving algorithm for the Monte Carlo method of Metropolis is presented. The technique is tested with different potential models and number of particles. The coupling of the method with neighbor lists, linked lists, Ewald sum and reaction field techniques is also analyzed. It is shown that the proposed algorithm is particularly suitable for computationally heavy intermolecular potentials.

The hypervolume Monte Carlo method at constant pressure applied to liquid methyl chloride

Abstract The hypervolume Monte Carlo (HVMC) in the isoenthalpic–isobaric ensemble (NpH), recently proposed by Fernandes and Freitas [1] has been applied to a molecular system. Thermal and structural properties as well as speed distribution functions of the liquid methyl chloride, obtained in a series of thermodynamics states, have been compared with NpT molecular dynamics (MD) [2] , [3] and some experimental results [4] . The agreement between the calculated and experimental densities is fairly good and the comparison with molecular dynamics results is excellent.