Ag TDDFT (OBSOLETE!)

The loss function of Ag

The loss function, related to a finite momentum transfer process is determined. The q-vector is defined in the <qpointset> element in the input file.

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet href="inputtohtml.xsl" type="text/xsl"?>
 
<input xsi:noNamespaceSchemaLocation="../../xml/excitinginput.xsd"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsltpath="../../xml/"
    scratchpath="/tmp/chm/1">
 
    <title>Loss function of Ag</title>
 
    <structure speciespath="../../species/">
        <crystal scale="3.86">
            <basevect>1.0 1.0 0.0</basevect>
            <basevect>1.0 0.0 1.0</basevect>
            <basevect>0.0 1.0 1.0</basevect>
        </crystal>
        <species speciesfile="Ag.xml">
            <atom coord="0.0  0.0  0.0" />
        </species>
    </structure>
 
    <groundstate ngridk="10  10  10" />
 
    <xs xstype="TDDFT" nosym="true" ngridk="10  10  10" vkloff="0.05 0.15 0.25"
        nempty="60" lmaxapwwf="5" lmaxemat="5" gqmax="2.0" broad="0.004"
        tevout="true">
        <dosWindow intv="0.0 2.5" points="500" />
        <tddft fxctype="RPA"/>
        <qpointset>
            <qpoint>0.0 0.0 0.1</qpoint>
        </qpointset>
    </xs>
 
</input>

The xc kernel is set to "RPA". It can, e.g., be changed to "ALDA" in the context of finite momentum transfer.

To start the calculation simply invoke the exciting executable

../../bin/excitingser

The xmgrace file can be easily generated from the LOSS*.xml files via the XSLT template:

xsltproc LOSS_to_xmgrace.xsl LOSS_FXC00_QMT001.OUT.xml > LOSS_FXC00_QMT001.OUT.xml.agr

View the xmgrace file:

xmgrace LOSS_FXC00_QT001.OUT.xml.agr

Alternatively, the loss function can be calculated using the ALDA xc kernel by changing the fxctype attribute in <tddft> element of the input file:

<tddft ... fxctype="ALDA" ...

Moreover, the Kohn-Sham response function and the matrix elements do not have to be recalculated upon a change in the xc kernel. This can be avoided setting the
resumefromkernel attribute to true inside the <tddft> element.

<tddft ... resumefromkernel="true" ...

Finally, the groundstate calculation can be skipped by adding the do attribute:

<groundstate ... do="skip" ...

The xmgrace file is again generated from the LOSS*.xml files via the XSLT template:

xsltproc LOSS_to_xmgrace.xsl LOSS_FXC05_QMT001.OUT.xml > LOSS_FXC05_QMT001.OUT.xml.agr

Here both results, from the RPA and the ALDA, are compared: