pymatgen.phonon.ir_spectra module¶
This module provides classes to handle the calculation of the IR spectra This implementation is adapted from Abipy https://github.com/abinit/abipy where it was originally done by Guido Petretto and Matteo Giantomassi

class
IRDielectricTensor
(oscillator_strength, ph_freqs_gamma, epsilon_infinity, structure)[source]¶ Bases:
monty.json.MSONable
Class to handle the Ionic Dielectric Tensor The implementation is adapted from Abipy See the definitions Eq.(5354) in :cite:`Gonze1997` PRB55, 10355 (1997).
 Parameters
oscillatator_strength – IR oscillator strengths as defined in Eq. 54 in :cite:`Gonze1997` PRB55, 10355 (1997).
ph_freqs_gamma – Phonon frequencies at the Gamma point
epsilon_infinity – electronic susceptibility as defined in Eq. 29.
structure – A Structure object corresponding to the structure used for the calculation.

get_ir_spectra
(broad=5e05, emin=0, emax=None, divs=500)[source]¶ The IR spectra is obtained for the different directions
 Parameters
broad – a list of broadenings or a single broadening for the phonon peaks
emax (emin,) – minimum and maximum energy in which to obtain the spectra
divs – number of frequency samples between emin and emax
 Returns
 divs array with the frequencies at which the
dielectric tensor is calculated
 dielectric_tensor: divsx3x3 numpy array with the dielectric tensor
for the range of frequencies
 Return type
frequencies

get_plotter
(components=('xx', ), reim='reim', broad=5e05, emin=0, emax=None, divs=500, **kwargs)[source]¶ Return an instance of the Spectrum plotter containing the different requested components
 Parameters
components – A list with the components of the dielectric tensor to plot. Can be either two indexes or a string like ‘xx’ to plot the (0,0) component
reim – If ‘re’ (im) is present in the string plots the real (imaginary) part of the dielectric tensor
emax (emin,) – minimum and maximum energy in which to obtain the spectra
divs – number of frequency samples between emin and emax

get_spectrum
(component, reim, broad=5e05, emin=0, emax=None, divs=500, label=None)[source]¶ component: either two indexes or a string like ‘xx’ to plot the (0,0) component reim: only “re” or “im” broad: a list of broadenings or a single broadening for the phonon peaks

property
max_phfreq
¶ Maximum phonon frequency

property
nph_freqs
¶ Number of phonon frequencies

plot
(components=('xx', ), reim='reim', show_phonon_frequencies=True, xlim=None, ylim=None, **kwargs)[source]¶ Helper function to generate the Spectrum plotter and directly plot the results
 Parameters
components – A list with the components of the dielectric tensor to plot. Can be either two indexes or a string like ‘xx’ to plot the (0,0) component
reim – If ‘re’ (im) is present in the string plots the real (imaginary) part of the dielectric tensor
show_phonon_frequencies – plot a dot where the phonon frequencies are to help identify IR inactive modes
Keyword arguments controlling the display of the figure:
kwargs
Meaning
title
Title of the plot (Default: None).
show
True to show the figure (default: True).
savefig
“abc.png” or “abc.eps” to save the figure to a file.
size_kwargs
Dictionary with options passed to fig.set_size_inches e.g. size_kwargs=dict(w=3, h=4)
tight_layout
True to call fig.tight_layout (default: False)
ax_grid
True (False) to add (remove) grid from all axes in fig. Default: None i.e. fig is left unchanged.
ax_annotate
Add labels to subplots e.g. (a), (b). Default: False