CHGNetQhaMaker

class atomate2.forcefields.flows.qha.CHGNetQhaMaker(name='CHGNet QHA Maker', initial_relax_maker=<factory>, eos_relax_maker=<factory>, phonon_maker=<factory>, linear_strain=(-0.05, 0.05), number_of_frames=6, t_max=None, pressure=None, ignore_imaginary_modes=False, skip_analysis=False, eos_type='vinet', analyze_free_energy_kwargs=<factory>)[source]

Bases: CommonQhaMaker

Perform quasi-harmonic approximation.

First relax a structure using relax_maker. Then perform a series of deformations on the relaxed structure, and then compute harmonic phonons for each deformed structure. Finally, compute Gibb’s free energy.

Parameters:

  • name (str) – Name of the flows produced by this maker.

  • initial_relax_maker (.ForceFieldRelaxMaker | None) – Maker to relax the input structure.

  • eos_relax_maker (.ForceFieldRelaxMaker | None) – Maker to relax deformed structures for the EOS fit. The volume has to be fixed!

  • phonon_maker (.PhononMaker) – Maker to compute phonons. The volume has to be fixed! The beforehand relaxation could be switched off.

  • linear_strain (tuple[float, float]) – Percentage linear strain to apply as a deformation, default = -5% to 5%.

  • number_of_frames (int) – Number of strain calculations to do for EOS fit, default = 6.

  • t_max (float | None) – Maximum temperature until which the QHA will be performed

  • pressure (float | None) – Pressure at which the QHA will be performed (default None, no pressure)

  • skip_analysis (bool) – Skips the analysis step and only performs EOS and phonon computations.

  • ignore_imaginary_modes (bool) – By default, volumes where the harmonic phonon approximation shows imaginary will be ignored

  • eos_type (supported_eos) – Equation of State type used for the fitting. Defaults to vinet.

  • analyze_free_energy_kwargs (dict)

property prev_calc_dir_argname: None

Name of argument informing static maker of previous calculation directory.

As this differs between different DFT codes (e.g., VASP, CP2K), it has been left as a property to be implemented by the inheriting class.

Note: this is only applicable if a relax_maker is specified; i.e., two calculations are performed for each ordering (relax -> static)