VaspGibbs

A simple way to get Gibbs free energy from Vasp calculations

Installation

pip install coming soon. For now copy vasp_gibbs to you working directory or add this folder to your PATH:

git clone https://github.com/ftherrien/VaspGibbs.git
echo "export PATH=$PATH:$PWD/VaspGibbs" >> $HOME/.bashrc
source $HOME/.bashrc

Usage

In a folder with a finished vasp calculation, run

vasp_gibbs

vasp_gibbs will rerun vasp to get vibration modes and output the gibbs free energy of your system.

Use -o (only) or -t(top) to specify a set of atoms for which to calculate vibration modes. Examples:

  • -o C O would only compute vibration modes associated with C and O keeping all other atoms fixed.
  • -o 1 3 6 would compute vibration modes associated with the first, third and sixth atoms in the POSCAR keeping all other atoms fixed.
  • -t 10 would compute vibration modes associated with the first 10 atoms starting from the top of the unit cell along the c axis.

This can be useful when computing free energy differences between systems where one part of the system does not change, e.g. adsorption free energies.

To run vasp in parallel call:

vasp_gibbs -n [number of proc] -m [mpi executable] -v [vasp executable]

By default srun and `vasp_std are used.

Under development

Currently working on reading the OUTCAR and computing gibbs free energy corrections. The features stated above should already work.

GitHub

View Github