Phonon3¶
This WorkChain calculated the 3rd order force constants using phono3py. This WorkChain requires one of the plugins for VASP, QuantumESPRESSO and LAMMPS described in phonon WorkChain. Nonanalytical corrections can be calculated from the Born effective charges and dielectric tensor which are only implemented for VASP plugin.

PhononPhono3py
(structure, ph_settings, es_settings[, optimize=True, use_nac=False, pressure= 0.0, calculate_fc=False])¶ Parameters:  structure – StructureData object that contains the crystal unit cell structure.
 ph_settings – Dict data object that contains the phonopy input parameters.
 es_settings – Dict object that contains the calculator input parameters. These parameters depends on the code used (see workchains/launcher examples)
 use_nac – (optional) BooleanData object. Determines if nonanalytical corrections will be included in the phonon calculations. By default this option is False.
 optimize – (optional) BooleanData object. Determines if a crystal unit cell optimization is performed or not before the phonon calculation. By default this option is True.
 pressure – (optional) FloatData object. If optimize is True, this sets the external pressure (in kB) at which the unit cell optimization is preformed. By default this option takes value 0 kB.
 calculate_fc – (optional) BooleanData object. Determines if the 2on and 3rd order force constants are calculated. By default this option is False.
 chunks – (optional) Int object that defines the maximum number of calculation to submit simultaneously. The next set of calculation will not be submitted until the previous set is finished.
 data_sets – (optional) ForceSets object that contains the forces and displacements of a previously calculation. This data_set can be the output of either phonon3 or phonon WorkChains.
The results outputs of this WorkChain are the following :
 data_sets: ForceSetsData object that contains the information of supercells with displacements and forces. Check
 force_constants_2order: ForceConstantsData object that contains the 2ond order force constants.
 force_constants_3order: ForceConstantsData object that contains the 3rd order force constants.
 final_structure: StructureData containing the optimized structure.
The ForceSetsData object obtained as a output of phonon3 WorkChain can be also in harmonic phonon calculation without modification.