science/py-symfc 1.3.1 DragonFly

Atomic vibrations in crystals are often conveniently described using the phonon model. In this model, the crystal potential is expanded into a Taylor series with respect to atomic displacements from their equilibrium positions, and the expansion coefficients are referred to as force constants.

Predicting phonon properties through computer simulations is becoming increasingly popular, with the supercell approach being one of the techniques employed for phonon calculations. In this method, force constants are derived from datasets of atomic forces and displacements obtained from supercell snapshots, which feature various configurations of atomic displacements.

While force constants possess specific symmetries, those computed from displacement-force datasets often do not adhere to these symmetries due to factors such as numerical noise or approximations used. Symfc is a software designed to compute force constants from displacement-force datasets in the supercell approach, ensuring they meet the required symmetry constraints.