title: Determination of the solid-fluid coexistence of the n - 6 Lennard-Jones system from free energy calculations.
abstract: The solid-fluid coexistence properties of the n - 6 Lennard-Jones system, n from 7 to 12, are reported. The procedure relies on determining Helmholtz free energy curves as a function of volume for each phase independently, from several NVT simulations, and then connecting it to points of known absolute free energy. For n = 12 this requires connecting the simulated points to states of very low densities on the liquid phase, and to a harmonic crystal for the solid phase, which involves many extra simulations for each temperature. For the reference points of the remaining systems, however, the free energy at a given density and temperature can be calculated relative to the n = 12 system. The method presented here involves a generalization of the multiple histogram method to combine simulations performed with different potentials, provided they visit overlapping regions of the phase space, and allows for a precise calculation of relative free energies. The densities, free energies, average potential energies, pressure, and chemical potential at coexistence are presented for up to T∗ = 5.0 and new estimations of the triple points are given for the n - 6 Lennard-Jones system.
authors.affiliation: Departamento de Física and I3N, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: J M G
authors.initials: JM
authors.lastname: Sousa
authors.forename: A L
authors.initials: AL
authors.lastname: Ferreira
authors.forename: M A
authors.initials: MA
authors.lastname: Barroso