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- Letter
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Monte Carlo simulations in the unconstrained ensemble
Phys. Rev. E 103, L061303 – Published 21 June, 2021
DOI: https://doi.org/10.1103/PhysRevE.103.L061303
Abstract
The unconstrained ensemble describes completely open systems whose control parameters are the chemical potential, pressure, and temperature. For macroscopic systems with short-range interactions, thermodynamics prevents the simultaneous use of these intensive variables as control parameters, because they are not independent and cannot account for the system size. When the range of the interactions is comparable with the size of the system, however, these variables are not truly intensive and may become independent, so equilibrium states defined by the values of these parameters may exist. Here, we derive a Monte Carlo algorithm for the unconstrained ensemble and show that simulations can be performed using the chemical potential, pressure, and temperature as control parameters. We illustrate the algorithm by applying it to physical systems where either the system has long-range interactions or is confined by external conditions. The method opens up an avenue for the simulation of completely open systems exchanging heat, work, and matter with the environment.
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References (32)
- N. Metropolis, A. W. Rosenbluth, M. N. Rosenbluth, A. N. Teller, and E. Teller, J. Chem. Phys. 21, 1087 (1953).
- D. Frenkel and B. Smit, Understanding Molecular Simulation: From Algorithms to Applications (Academic, San Diego, 2002).
- D. P. Landau and K. Binder, A Guide to Monte Carlo Simulations in Statistical Physics (Cambridge University Press, Cambridge, UK, 2009)
- M. Creutz, Phys. Rev. Lett. 50, 1411 (1983).
- G. E. Norman and V. S. Filinov, High Temp. (USSR) 7, 216 (1969).
- D. A. Kofke and E. D. Glandt, Mol. Phys. 64, 1105 (1988).
- W. W. Wood, J. Chem. Phys. 48, 415 (1968).
- I. R. McDonald, Mol. Phys. 23, 41 (1972).
- M. Schoen, D. J. Diestler, and J. H. Cushman, Phys. Rev. B 47, 5603 (1993).
- A. Z. Panagiotopoulos, Mol. Phys. 61, 813 (1987).
- A. Z. Panagiotopoulos, N. Quirke, M. R. Stapleton, and D. J. Tildesley, Mol. Phys. 63, 527 (1988).
- H. B. Callen, Thermodynamics and an Introduction to Thermostatistics (Wiley, New York, 1985).
- T. L. Hill, Statistical Mechanics. Principles and Selected Applications (Dover, New York, 1987).
- G. Orkoulas and D. P. Noon, J. Chem. Phys. 131, 161106 (2009).
- N. B. Wilding and P. Sollich, Europhys. Lett. 101, 10004 (2013).
- T. L. Hill, Thermodynamics of Small Systems (Dover, New York, 2013).
- M. Schoen, D. J. Diestler, and J. H. Cushman, J. Chem. Phys. 100, 7707 (1994).
- By a confined system we mean a system in which one of the typical lengths defining its size, say , is such that is not much larger than 1, where is the range of the intermolecular interaction.
- I. Latella, A. Pérez-Madrid, A. Campa, L. Casetti, and S. Ruffo, Phys. Rev. E 95, 012140 (2017).
- A. Campa, L. Casetti, I. Latella, and S. Ruffo, J. Stat. Mech. (2020) 014004.
- A. Campa, T. Dauxois, D. Fanelli, and S. Ruffo, Physics of Long-Range Interacting Systems (Oxford University Press, Oxford, UK, 2014); A. Campa, T. Dauxois, and S. Ruffo, Phys. Rep. 480, 57 (2009).
- I. Latella, A. Pérez-Madrid, A. Campa, L. Casetti, and S. Ruffo, Phys. Rev. Lett. 114, 230601 (2015).
- D. Bedeaux, S. Kjelstrup, and S. K. Schnell, Nanothermodynamics – General Theory, 1st ed. (PoreLab, Trondheim, 2020).
- See Supplemental Material at http://link.aps.org/supplemental/10.1103/PhysRevE.103.L061303 for an explicit integration of Eq. (1), a detailed derivation of Eq. (3), and for the explicit expressions of the acceptance probabilities used in the considered examples, which includes Ref. [32].
- M. Schmidt and H. Löwen, Phys. Rev. E 55, 7228 (1997).
- R. Evans, J. Phys.: Condens. Matter 2, 8989 (1990).
- N. F. Carnahan and K. E. Starling, J. Chem. Phys. 51, 635 (1969).
- L. L. Lee, J. Chem. Phys. 103, 9388 (1995).
- F. Sciortino, S. Mossa, E. Zaccarelli, and P. Tartaglia, Phys. Rev. Lett. 93, 055701 (2004).
- S. Mossa, F. Sciortino, P. Tartaglia, and E. Zaccarelli, Langmuir 20, 10756 (2004).
- A. P. Santos, J. Pekalski, and A. Z. Panagiotopoulos, Soft Matter 13, 8055 (2017).
- M. A. Miller, L. M. Amon, and W. P. Reinhardt, Chem. Phys. Lett. 331, 278 (2000).