Calculation of phase diagrams in the multithermal-multibaric ensemble

Authors: Pablo M. Piaggi1*, Michele Parrinello2*

  1. Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
  2. Department of Chemistry and Applied Biosciences, ETH Zurich, c/o USI Campus, Via Giuseppe Buffi 13, CH-6900, Lugano, Switzerland and Facoltà di Informatica, Istituto di Scienze Computazionali, and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Università della Svizzera italiana (USI), Via Giuseppe Buffi 13, CH-6900, Lugano, Switzerland
  • Corresponding authors emails: ppiaggi@princeton.edu, parrinello@phys.chem.ethz.ch

DOI10.24435/materialscloud:2019.0087/v1 (version v1, submitted on 11 December 2019)

How to cite this entry

Pablo M. Piaggi, Michele Parrinello, Calculation of phase diagrams in the multithermal-multibaric ensemble, Materials Cloud Archive (2019), doi: 10.24435/materialscloud:2019.0087/v1.

Description

From the Ising model and the Lennard-Jones fluid to water and the iron-carbon system, phase diagrams are an indispensable tool to understand phase equilibria. Despite the effort of the simulation community, the calculation of a large portion of a phase diagram using computer simulation is still today a significant challenge. Here, we propose a method to calculate phase diagrams involving liquid and solid phases by the reversible transformation of the liquid and the solid. To this end, we introduce an order parameter that breaks the rotational symmetry and we leverage our recently introduced method to sample the multithermal-multibaric ensemble. In this way, in a single molecular dynamics simulation, we are able to compute the liquid-solid coexistence line for entire regions of the temperature and pressure phase diagram. We apply our approach to the bcc-liquid phase diagram of sodium and the fcc-bcc-liquid phase diagram of aluminum.

This repository contains the input files to reproduce the results of the paper mentioned above. The results are divided into two zip files Al.zip and Na.zip for simulations of aluminum and sodium, respectively. Inside each folder there is an example for the calculation of free energies at constant temperature and pressure, and the input files and results of the multithermal-multibaric simulations.

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Files

File name Size Description
Al.zip
MD5MD5: a00f4d16fb78dcde8fa7ec9ca9705160
129.6 MiB Input files and results for the simulations of aluminum. Simulations were performed with Lammps and Plumed.
Na.zip
MD5MD5: b6a06c8dcad43c30e75479f12937fd0f
28.0 MiB Input files and results for the simulations of sodium. Simulations were performed with Lammps and Plumed.
README.md
MD5MD5: d13b46c97eeb065850d4acebd8ee0590
1.3 KiB README file. Describes contents of the other files.

License

Files and data are licensed under the terms of the following license: Creative Commons Attribution 4.0 International.

External references

Journal reference (Paper in which the method is discussed. )
P. M. Piaggi, M. Parrinello, J. Chem. Phys. 150, 244119 (2019) doi:10.1063/1.5102104

Keywords

enhanced sampling multithermal-multibaric MARVEL/DD1 free energy VES phase diagrams sodium aluminum

Version history

11 December 2019 [This version]