# pymatgen.phonon.dos module¶

class CompletePhononDos(structure, total_dos, pdoss)[source]

This wrapper class defines a total dos, and also provides a list of PDos.

Parameters: structure – Structure associated with this particular DOS. total_dos – total Dos for structure pdoss – The pdoss are supplied as an {Site: Densities}
pdos

Dict of partial densities of the form {Site:Densities}

as_dict()[source]

Json-serializable dict representation of CompletePhononDos.

classmethod from_dict(d)[source]

Returns CompleteDos object from dict representation.

get_element_dos()[source]

Get element projected Dos.

Returns: Dos} dict of {Element
get_site_dos(site)[source]

Get the Dos for a site.

Parameters: site – Site in Structure associated with CompletePhononDos. PhononDos containing summed orbital densities for site.
class PhononDos(frequencies, densities)[source]

Bases: monty.json.MSONable

Basic DOS object. All other DOS objects are extended versions of this object.

Parameters: frequencies – A sequences of frequencies in THz densities – A list representing the density of states.
as_dict()[source]

Json-serializable dict representation of PhononDos.

cv(t, structure=None)[source]

Constant volume specific heat C_v at temperature T obtained from the integration of the DOS. Only positive frequencies will be used. Result in J/(K*mol-c). A mol-c is the abbreviation of a mole-cell, that is, the number of Avogadro times the atoms in a unit cell. To compare with experimental data the result should be divided by the number of unit formulas in the cell. If the structure is provided the division is performed internally and the result is in J/(K*mol)

Parameters: t – a temperature in K structure – the structure of the system. If not None it will be used to determine the numer of formula units Constant volume specific heat C_v
entropy(t, structure=None)[source]

Vibrational entropy at temperature T obtained from the integration of the DOS. Only positive frequencies will be used. Result in J/(K*mol-c). A mol-c is the abbreviation of a mole-cell, that is, the number of Avogadro times the atoms in a unit cell. To compare with experimental data the result should be divided by the number of unit formulas in the cell. If the structure is provided the division is performed internally and the result is in J/(K*mol)

Parameters: t – a temperature in K structure – the structure of the system. If not None it will be used to determine the numer of formula units Vibrational entropy
classmethod from_dict(d)[source]

Returns PhononDos object from dict representation of PhononDos.

get_interpolated_value(frequency)[source]

Returns interpolated density for a particular frequency.

Parameters: frequency – frequency to return the density for.
get_smeared_densities(sigma)[source]

Returns the densities, but with a Gaussian smearing of std dev sigma applied.

Parameters: sigma – Std dev of Gaussian smearing function. Gaussian-smeared densities.
helmholtz_free_energy(t, structure=None)[source]

Phonon contribution to the Helmholtz free energy at temperature T obtained from the integration of the DOS. Only positive frequencies will be used. Result in J/mol-c. A mol-c is the abbreviation of a mole-cell, that is, the number of Avogadro times the atoms in a unit cell. To compare with experimental data the result should be divided by the number of unit formulas in the cell. If the structure is provided the division is performed internally and the result is in J/mol

Parameters: t – a temperature in K structure – the structure of the system. If not None it will be used to determine the numer of formula units Phonon contribution to the Helmholtz free energy
ind_zero_freq[source]

Index of the first point for which the freqencies are equal or greater than zero.

internal_energy(t, structure=None)[source]

Phonon contribution to the internal energy at temperature T obtained from the integration of the DOS. Only positive frequencies will be used. Result in J/mol-c. A mol-c is the abbreviation of a mole-cell, that is, the number of Avogadro times the atoms in a unit cell. To compare with experimental data the result should be divided by the number of unit formulas in the cell. If the structure is provided the division is performed internally and the result is in J/mol

Parameters: t – a temperature in K structure – the structure of the system. If not None it will be used to determine the numer of formula units Phonon contribution to the internal energy
zero_point_energy(structure=None)[source]

Zero point energy energy of the system. Only positive frequencies will be used. Result in J/mol-c. A mol-c is the abbreviation of a mole-cell, that is, the number of Avogadro times the atoms in a unit cell. To compare with experimental data the result should be divided by the number of unit formulas in the cell. If the structure is provided the division is performed internally and the result is in J/mol

Parameters: t – a temperature in K structure – the structure of the system. If not None it will be used to determine the numer of formula units Phonon contribution to the internal energy