# PH¶

## Description¶

Plugin for the Quantum Espresso ph.x executable.

## Supported codes¶

• tested from ph.x v5.0 onwards.

## Inputs¶

• parent_calculation, can either be a PW calculation to get the ground state on which to compute the phonons, or a PH calculation in case of restarts.

Note: There are no direct links between calculations. The use_parent_calculation will set a link to the RemoteFolder attached to that calculation. Alternatively, the method use_parent_folder can be used to set this link directly.

• qpoints, class KpointsData Reciprocal space points on which to build the dynamical matrices. Can either be a mesh or a list of points. Note: up to QE 5.1 only either an explicit list of 1 qpoint (1 point only) can be provided, or a mesh (containing gamma).

• parameters, class ParameterData Input parameters of ph.x, as a nested dictionary, mapping the input of QE. Example:

{"INPUTPH":{"ethr-ph":1e-16},
}


A full list of variables and their meaning is found in the ph.x documentation.

Following keywords are already taken care of by AiiDA:

'INPUTPH', 'outdir': scratch directory
'INPUTPH', 'prefix': file prefix
'INPUTPH', 'iverbosity': file prefix
'INPUTPH', 'fildyn': file prefix
'INPUTPH', 'ldisp': logic displacement
'INPUTPH', 'nq1': q-mesh on b1
'INPUTPH', 'nq2': q-mesh on b2
'INPUTPH', 'nq3': q-mesh on b3
'INPUTPH', 'qplot': flag for list of qpoints

• settings, class ParameterData (optional) An optional dictionary that activates non-default operations. Possible values are:

• ‘PARENT_CALC_OUT_SUBFOLDER’: string. The subfolder of the parent scratch to be copied in the new scratch.
• ‘PREPARE_FOR_D3’: boolean. If True, more files are created in preparation of the calculation of a D3 calculation.
• ‘NAMELISTS’: list of strings. Specify all the list of Namelists to be printed in the input file.
• ‘PARENT_FOLDER_SYMLINK’: boolean # If True, create a symlnk to the scratch of the parent folder, otherwise the folder is copied (default: False)
• ‘CMDLINE’: list of strings. parameters to be put after the executable and before the input file. Example: [“-npool”,”4”] will produce ph.x -npool 4 < aiida.in
• ‘ADDITIONAL_RETRIEVE_LIST’: list of strings. Extra files to be retrieved. By default, dynamical matrices, text output and main xml files are retrieved.

## Outputs¶

There are several output nodes that can be created by the plugin, according to the calculation details. All output nodes can be accessed with the calculation.out method.

• output_parameters ParameterData Contains small properties. Example: dielectric constant, warnings (possible error messages generated in the run). calculation.out.output_parameters can also be accessed by the calculation.res shortcut. Furthermore, various dynamical_matrix_* keys are created, each is a dictionary containing the keys q_point and frequencies.

## Errors¶

Errors of the parsing are reported in the log of the calculation (accessible with the verdi calculation logshow command). Moreover, they are stored in the ParameterData under the key warnings, and are accessible with Calculation.res.warnings.