euphonic-intensity-map

The euphonic-intensity-map program can be used to plot a 2D intensity map either along a specific trajectory from precalculated phonon frequencies and eigenvectors, or along a recommended reciprocal space path from force constants.

For example, to plot a coherent neutron-weighted intensity map from CASTEP force constants along a recommended q-point path, one could run:

euphonic-intensity-map --weighting coherent --energy-broadening 1.5 quartz.castep_bin

Or, to plot a DOS-weighted intensity from Phonopy phonon frequencies:

euphonic-intensity-map --weighting dos --energy-unit THz --energy-broadening 0.15 band.yaml

To see all the command line options, run:

euphonic-intensity-map -h

You can also see the available command line options below

Command Line Options

Plots a 2D intensity map from the file provided. If a force constants file is provided, a band structure path is generated using Seekpath

usage: euphonic-intensity-map [-h] [--asr [{reciprocal,realspace}]]
                              [--dipole-parameter DIPOLE_PARAMETER]
                              [--use-c | --disable-c] [--n-threads N_THREADS]
                              [--weights {dos,coherent}]
                              [--weighting {dos,coherent}]
                              [--temperature TEMPERATURE]
                              [--grid GRID GRID GRID | --grid-spacing GRID_SPACING]
                              [-s SAVE_TO] [--title TITLE] [--x-label X_LABEL]
                              [--y-label Y_LABEL] [--e-min E_MIN]
                              [--e-max E_MAX] [--energy-unit ENERGY_UNIT]
                              [--ebins EBINS]
                              [--energy-broadening ENERGY_BROADENING]
                              [--shape [{gauss,lorentz}]]
                              [--length-unit LENGTH_UNIT]
                              [--q-spacing Q_SPACING]
                              [--q-broadening Q_BROADENING] [--v-min V_MIN]
                              [--v-max V_MAX] [--cmap CMAP] [--btol BTOL]
                              filename

File I/O arguments

filename

Phonon data file. This should contain force constants or phonon mode data. Force constants formats: .yaml, force_constants.hdf5 (Phonopy); .castep_bin , .check (Castep); .json (Euphonic). Phonon mode data formats: {band,qpoints,mesh}.{hdf5,yaml} (Phonopy); .phonon (Castep); .json (Euphonic)

q-point sampling arguments

“GRID” options relate to Monkhorst-Pack sampling for the Debye-Waller factor, and only apply when –weighting=coherent and –temperature is set. “Q” options relate to the x-axis of spectrum data.

--grid

Defines a Monkhorst-Pack grid.

--grid-spacing

q-point spacing of Monkhorst-Pack grid.

Default: 0.1

--length-unit

Length units; these will be inverted to obtain units of distance between q-points (e.g. “bohr” for bohr^-1).

Default: “angstrom”

--q-spacing

Target distance between q-point samples in 1/LENGTH_UNIT

Default: 0.025

--q-broadening, --qb

FWHM of broadening on q axis in 1/LENGTH_UNIT (no broadening if unspecified).

--btol

Distance threshold used for automatically splitting discontinuous segments of reciprocal space onto separate subplots. This is specified as a multiple of the median distance between q-points.

Default: 10.0

energy/frequency arguments

--e-min

Energy range minimum in ENERGY_UNIT

--e-max

Energy range maximum in ENERGY_UNIT

--energy-unit, -u

Energy units

Default: “meV”

--ebins

Number of energy bins

Default: 200

--energy-broadening, --eb

The FWHM of broadening on energy axis in ENERGY_UNIT (no broadening if unspecified).

--shape

Possible choices: gauss, lorentz

The broadening shape

Default: “gauss”

Force constants interpolation arguments

--asr

Possible choices: reciprocal, realspace

Apply an acoustic-sum-rule (ASR) correction to the data: “realspace” applies the correction to the force constant matrix in real space. “reciprocal” applies the correction to the dynamical matrix at each q-point.

--dipole-parameter

Set the cutoff in real/reciprocal space for the dipole Ewald sum; higher values use more reciprocal terms. If tuned correctly this can result in performance improvements. See euphonic-optimise-dipole-parameter program for help on choosing a good DIPOLE_PARAMETER.

Default: 1.0

Property-calculation arguments

--weights

Possible choices: dos, coherent

–weights is deprecated, please use –weighting instead

Default: “dos”

--weighting, -w

Possible choices: dos, coherent

Spectral weighting to plot: DOS, coherent inelastic neutron scattering

Default: “dos”

--temperature

Temperature in K; enable Debye-Waller factor calculation. (Only applicable when –weighting=coherent).

Plotting arguments

-s, --save-to

Save resulting plot to a file with this name

--title

Plot title

Default: “”

--x-label

Plot x-axis label

--y-label

Plot y-axis label

--v-min

Minimum of data range for colormap.

--v-max

Maximum of data range for colormap.

--cmap

Matplotlib colormap

Default: “viridis”