class matlantis_features.features.phonon.utils.PhononFrequency(force_constant: ndarray, supercell: ndarray, unit_cell_atoms: Union[MatlantisAtoms, Atoms])#

Bases: object

The class to calculate the phonon frequencies and modes from the force constant.

Methods

__init__(force_constant, supercell, …)

Initialize an instance.

get_frequency(kpts[, unit])

Calculate the phonon frequency for each k-point.

get_frequency_mode(kpts[, unit])

Calculate both the phonon frequency and the phonon mode for each k-point.
__init__(force_constant: ndarray, supercell: ndarray, unit_cell_atoms: Union[MatlantisAtoms, Atoms])#

Initialize an instance.

Parameters

  • force_constant (np.ndarray) – The force constant.

  • supercell (np.ndarray) – The supercell size used for the force constant
    calculation.

  • unit_cell_atoms (MatlantisAtoms or ASEAtoms) – The input primitive cell structure.

get_frequency(kpts: ndarray, unit: str = ‘meV’) → ndarray#

Calculate the phonon frequency for each k-point.

Parameters

  • kpts (ndarray) – The phonon wavevectors (k-points), expected to be a 2D ndarray with shape (n,3).

  • unit (str, optional) – The unit of phonon frequency. Must be one of: ‘meV’, ‘eV’, ‘THz’
    or ‘cm^-1’. Defaults to ‘meV’.

Returns

The phonon frequency.

Return type

ndarray

Raises

  • ValueError – If the kpts input is not a (n, 3) 2D ndarray.

  • ValueError – If the unit is not one of the allowed values.

get_frequency_mode(kpts: ndarray, unit: str = ‘meV’) → Tuple[ndarray, ndarray]#

Calculate both the phonon frequency and the phonon mode for each k-point.

Parameters

  • kpts (ndarray) – The phonon wavevectors (k-points), expected to be a 2D ndarray with shape (n,3).

  • unit (str, optional) – The unit of phonon frequency. Must be one of: ‘meV’, ‘eV’, ‘THz’
    or ‘cm^-1’. Defaults to ‘meV’.

Returns

The phonon frequency and the phonon mode.

Return type

tuple[ndarray, ndarray]

Raises

  • ValueError – If the kpts input is not a (n, 3) 2D ndarray.

  • ValueError – If the unit is not one of the allowed values.