quantum-espresso/PHonon/Doc/INPUT_Q2R.xml

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<?xml version="1.0" encoding="ISO-8859-1"?>
<?xml-stylesheet type="text/xsl" href="input_xx.xsl"?>
<!-- FILE AUTOMATICALLY CREATED: DO NOT EDIT, CHANGES WILL BE LOST -->
<input_description distribution="Quantum ESPRESSO" package="PHonon" program="q2r.x" >
<toc>
</toc>
<intro>
<b>Purpose of q2r.x:</b>
It reads force constant matrices C(q) produced by the <b>ph.x</b> code
for a grid of q-points and calculates the corresponding set
of interatomic force constants (IFC), C(R)
<b>Input data format:</b> [ ] = it depends
<b>Structure of the input data:</b>
========================================================================
<b>&amp;INPUT</b>
...specs of namelist variables...
<b>/</b>
[ nr1 nr2 nr3
nfile
file(1)
file(2)
...
file(nfile) ]
</intro>
<namelist name="INPUT" >
<var name="fildyn" type="CHARACTER" >
<status> REQUIRED
</status>
<info>
Input file name (must be specified).
<b>&quot;fildyn&quot;0</b> contains information on the q-point grid
<b>&quot;fildyn&quot;1-N</b> contain force constants C_n = C(q_n),
where <b>n = 1,...N</b>, where N is the number of
q-points in the irreducible brillouin zone.
Normally this should be the same as specified on input
to the phonon code.
In the non collinear/spin-orbit case the files
produced by <b>ph.x</b> are in .xml format. In this case
<ref>fildyn</ref> is the same as in the phonon code + the
.xml extension.
</info>
</var>
<var name="flfrc" type="CHARACTER" >
<status> REQUIRED
</status>
<info>
Output file containing the IFC in real space (must be specified)
</info>
</var>
<var name="zasr" type="CHARACTER" >
<default> &apos;no&apos;
</default>
<options>
<info>
Indicates the type of Acoustic Sum Rules used for the Born
effective charges.
Allowed values:
</info>
<opt val="'no'" >
no Acoustic Sum Rules imposed (default)
</opt>
<opt val="'simple'" >
previous implementation of the asr used
(3 translational asr imposed by correction of
the diagonal elements of the force-constants matrix)
</opt>
<opt val="'crystal'" >
3 translational asr imposed by optimized
correction of the IFC (projection)
</opt>
<opt val="'one-dim'" >
3 translational asr + 1 rotational asr
imposed by optimized correction of the IFC (the
rotation axis is the direction of periodicity; it
will work only if this axis considered is one of
the cartesian axis).
</opt>
<opt val="'zero-dim'" >
3 translational asr + 3 rotational asr
imposed by optimized correction of the IFC.
</opt>
<info>
Note that in certain cases, not all the rotational asr
can be applied (e.g. if there are only 2 atoms in a
molecule or if all the atoms are aligned, etc.).
In these cases the supplementary asr are cancelled
during the orthonormalization procedure (see below).
</info>
</options>
</var>
<var name="loto_2d" type="LOGICAL" >
<info>
set to <b>.true.</b> to activate two-dimensional treatment
of LO-TO splitting.
</info>
</var>
</namelist>
<choose>
<when test="file {fildyn}0 does not exist" >
<message>
If a file <b>&quot;fildyn&quot;0</b> is not found, the code will ignore variable
<ref>fildyn</ref> and will try to read from the following cards the missing
information on the q-point grid and file names:
</message>
<linecard>
<vargroup type="INTEGER" >
<var name="nr1" >
</var>
<var name="nr2" >
</var>
<var name="nr3" >
</var>
<info>
dimensions of the FFT grid formed by the q-point grid
</info>
</vargroup>
</linecard>
<card name="fileSpecs" nameless="1" >
<syntax>
<line>
<var name="nfile" type="INTEGER" >
<info>
number of files containing C(q_n), n=1,<ref>nfile</ref>
</info>
</var>
</line>
<table name="file_n" >
<rows start="1" end="nfile" >
<col name="file" type="CHARACTER" >
<info>
names of the files containing C(q_n), n=1,<ref>nfile</ref>
Note that the name and order of files is not important as
long as <b>q=0 is the first</b>.
</info>
</col>
</rows>
</table>
</syntax>
</card>
</when>
</choose>
</input_description>