Phonons

Element: phonons

Phonon frequencies and eigen vectors for an arbitrary q-point.

contains: qpointset (optional)
phonondos (optional)
phonondispplot (optional)
reformatdynmat (optional)
interpolate (optional)
parts (optional)
XPath: /input/phonons

This element allows for specification of the following attributes: ngridq (required), deltaph, do, phonontype, reduceq

Attribute: deltaph

Phonon calculations are performed by constructing a supercell corresponding to a particular ${\bf q}$-vector and making a small periodic displacement of the atoms. The magnitude of this displacement is given by deltaph. This should not be made too large, as anharmonic terms could then become significant, neither should it be too small as this can introduce numerical error.

Type: fortrandouble
Default: "0.03d0"
Use: optional
XPath: /input/phonons/@deltaph


Attribute: do

Decides if the phonon calculation is skipped or recalculated or continued from file.

Type: choose from:
fromscratch
skip
Default: "fromscratch"
Use: optional
XPath: /input/phonons/@do


Attribute: ngridq

Number of q grid points along the basis vector directions.

Type: integertriple
Use: required
XPath: /input/phonons/@ngridq


Attribute: phonontype

Decides which method (supercell or linear response) is used to perform the phonon calculation.

Type: choose from:
supercell
linearresponse
Default: "supercell"
Use: optional
XPath: /input/phonons/@phonontype


Attribute: reduceq

The attribute reduceq is set to "true" if the $q$-point set is to be reduced with the crystal symmetries.

Type: boolean
Default: "true"
Use: optional
XPath: /input/phonons/@reduceq

Element: phonondos

Phonon density of states.

Type: no content
XPath: /input/phonons/phonondos

This element allows for specification of the following attributes: ngrdos, nsmdos, ntemp, nwdos

Attribute: ngrdos

Type: no content
Default: "100"
Use: optional
XPath: /input/phonons/phonondos


Attribute: nsmdos

Type: no content
Default: ""
Use: optional
XPath: /input/phonons/phonondos


Attribute: ntemp

Number of temperatures points for the calculation of the thermodynamical properties from the phonon density of states.

Type: integer
Default: "10"
Use: optional
XPath: /input/phonons/phonondos/@ntemp


Attribute: nwdos

Type: no content
Default: "500"
Use: optional
XPath: /input/phonons/phonondos

Element: phonondispplot

Phonon dispersion plot.

contains: plot1d
XPath: /input/phonons/phonondispplot

Element: reformatdynmat

Reads in the dynamical matrix rows from the corresponding files and outputs them in the DYNMAT*.OUT files, taking into account symmetrization and the accoustic sumrule.

Type: no content
XPath: /input/phonons/reformatdynmat

Element: interpolate

Interpolates the phonon frequencies on a given q-point set.

Type: no content
XPath: /input/phonons/interpolate

This element allows for specification of the following attributes: ngridq (required), vqloff, writeeigenvectors

Attribute: ngridq

q-point grid for interpolation.

Type: integertriple
Use: required
XPath: /input/phonons/interpolate/@ngridq


Attribute: vqloff

The q-point offset vector in lattice coordinates.

Type: vect3d
Default: "0.0d0 0.0d0 0.0d0"
Use: optional
XPath: /input/phonons/interpolate/@vqloff


Attribute: writeeigenvectors

Set to true if the phonon eigenvectors are to be interpolated and output in addition to the phonon frequencies.

Type: boolean
Default: "false"
Use: optional
XPath: /input/phonons/interpolate/@writeeigenvectors

Reused Elements

The following elements can occur more than once in the input file. There for they are listed separately.

Data Types

The Input definition uses derived data types. These are described here.

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