FreeBird

Free energy calculators by Bayesian-inspired nested sampling and other integration techniques

Installation

FreeBird.jl is a Julia package. Install Julia first following the instructions in the download page.

Once Julia is installed, you can install the FreeBird package from the Julia REPL with:

julia> ] # press the "]" key on your keyboard to enter the Pkg manager

then

pkg> add FreeBird

Alternatively, you can install the package with:

using Pkg; Pkg.add("FreeBird")

Useful for installing the package in a script or a notebook.

Or, if you want to install a specific branch from GitHub, you can do so with:

pkg> add https://github.com/wexlergroup/FreeBird.jl#branch_name

Or, again, to install the package in a script or a notebook:

using Pkg; Pkg.add(url="https://github.com/wexlergroup/FreeBird.jl",rev="branch_name")

Remember to replace branch_name with the name of the branch you want to install.

To get back to the Julia REPL, press Ctrl+C or backspace (when the REPL cursor is at the beginning of the input).

References

The FreeBird.jl code paper on the Journal of Chemical Theory and Computation:

• Yang, R.; Chen, J.; Thibodeaux, D.; B. Wexler, R. FreeBird.jl: An Extensible Toolbox for Simulating Interfacial Phase Equilibria. J. Chem. Theory Comput. 2025. https://doi.org/10.1021/acs.jctc.5c01348

Published surface nested sampling work from Wexler group:

• Yang, M.; B. Pártay, L.; B. Wexler, R. Surface Phase Diagrams from Nested Sampling. Phys. Chem. Chem. Phys. 2024. https://doi.org/10.1039/D4CP00050A.
• Chatbipho, T.; Yang, R,; B. Wexler, R.; Pártay, L. B. Adsorbate phase transitions on nanoclusters from nested sampling. arXiv:2506.01295 2025 https://arxiv.org/abs/2506.01295

The nested sampling method:

• Pártay, L. B.; Csányi, G.; Bernstein, N. Nested Sampling for Materials. Eur. Phys. J. B 2021, 94 (8), 159. https://doi.org/10.1140/epjb/s10051-021-00172-1.

• Ashton, G.; Bernstein, N.; Buchner, J.; Chen, X.; Csányi, G.; Fowlie, A.; Feroz, F.; Griffiths, M.; Handley, W.; Habeck, M.; Higson, E.; Hobson, M.; Lasenby, A.; Parkinson, D.; Pártay, L. B.; Pitkin, M.; Schneider, D.; Speagle, J. S.; South, L.; Veitch, J.; Wacker, P.; Wales, D. J.; Yallup, D. Nested Sampling for Physical Scientists. Nat Rev Methods Primers 2022, 2 (1), 39. https://doi.org/10.1038/s43586-022-00121-x.