calphy

calphy

calphy(pronounced cal-phee) is a Python library and command line tool for calculation of free energies. It uses LAMMPS as the molecular dynamics driver to enable calculation of free energies using thermodynamic integration in a completely automated and efficient manner. The various methods that calphy can perform are:

• and for both solid and liquid phases at the given thermodynamic conditions using non-equilibrium Hamiltonian interpolation.
• and , temperature dependence of Gibbs and Helmholtz free energies using the reversible scaling approach.
• Calculation of solid-solid or solid-liquid phase transition temperatures.
• Calculation of coexistence lines using dynamic Clausius-Clapeyron integration.
• Calculation of specific heat as a function of temperature.
• Calculation of and for multicomponent systems using alchemical transformations.
• Upsampling calculations.

Calphy works with all interatomic potentials implemented in LAMMPS and can obtain reliable results with low error bars in as low as 50 ps of simulation time with less than 3000 atoms. More information about the methods in calphy can be found in the associated publication.

Installation, examples and documentation

• Read the calphy installation instructions and documentation including examples here.

• For a description of the methods and algorithms implemented in calphy, please see the associated publication.

• For a set of examples presented in the calphy publication, please see here.

Citing calphy

If you find calphy useful, please consider citing:
Menon, Sarath, Yury Lysogorskiy, Jutta Rogal, and Ralf Drautz.
“Automated Free Energy Calculation from Atomistic Simulations.” Physical Review Materials 5(10), 2021
DOI: 10.1103/PhysRevMaterials.5.103801

Download bibtex here