A Monte Carlo method for chemical potential determination in single and multiple occupancy crystals
1 Department of Physics, University of Bath - Bath BA2 7AY, UK
2 King's College London, Department of Mathematics - Strand, London WC2R 2LS, UK
Received: 25 October 2012
Accepted: 10 December 2012
We describe a Monte Carlo scheme which, in a single simulation, yields a measurement of the chemical potential of a crystalline solid. Within the isobaric ensemble, this immediately provides an estimate of the system free energy, with statistical uncertainties that are determined precisely and transparently. An extension to multiple occupancy (“cluster”) solids permits the direct determination of the cluster chemical potential and hence the equilibrium conditions. We apply the method to a model exhibiting cluster crystalline phases, where we find evidence for an infinite cascade of critical points terminating coexistence between crystals of differing site occupancies.
PACS: 05.10.Ln – Monte Carlo methods / 61.50.Ks – Crystallographic aspects of phase transformations; pressure effects / 64.75.Xc – Phase separation and segregation in colloidal systems
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