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<p>View case.struct of the supercell in StructGen of w2web. If the
supercell has a space group, it will show what it is. If it has
no space group, it should instead have a general lattice
highlighted such as "P".</p>
<p>The WIEN2k 19.1 usersguide [1] states on page 110 under section
"6.2 SGROUP":</p>
<p><i>This program uses information from case.struct (lattice type,
lattice constants, atomic positions)</i><i><br>
</i><i>and determines the spacegroup ...</i><br>
</p>
<p>From the above statement, you can probably derive that a purpose
of the sgroup program is to take a case.struct as input having a
structure defined in a general lattice having an unknown
spacegroup and gives as output what space group fits the
structure. Therefore, the space group should be displayed after
clicking "x sgroup" button in w2web or should be found in the
case.outputsgroup file.<br>
</p>
<p>Since Phonopy can only parse space group 1_P1 as input [2], the
output case.struct files from it are probably general P lattice
that would also have space group 1_P1. Phonopy might not add the
space group or special labels in the output case.struct files. If
so, the special labels may need to be added manually (based on
[3]) to all atoms so that "x sgroup" finds space group 1_P1 else
it might reduce the cell to one with higher symmetry. <br>
</p>
<p>The triclinic space group P1 [4] has the lowest symmetry were
there are no restrictions on the values of the cell parameters [5]
in which it should have the advantage that any structure is
definable in it. The disadvantage that comes from that is it
computationally extensive for WIEN2k calculations which is
probably not surprising with a higher number of inequivalent
positions compared to if you were able to group atomic positions
into sets of equivalent position to make use of symmetry [6,7].
Typically WIEN2k users are interested in comparing a structure
with slight parameter changes [9,10] in which a change in basis
vectors of the structure [10] would be undesirable.</p>
<p>So, you would need to use your crystallographic knowledge to use
"x sgroup" as to not have GIGO [11] that you may have learned such
as be reading the Volumes on International Tables for
Crystallography [12].<br>
</p>
<p>Bilbao Crystallographic Server's Subgroups might also be of
interest because at [13] it mentions it can list other compatible
space groups for a supercell.<br>
</p>
<p><br>
</p>
[1]
<a class="moz-txt-link-freetext" href="http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf">http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf</a><br>
[2]
<a class="moz-txt-link-freetext" href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14219.html">https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14219.html</a><br>
[3] <a class="moz-txt-link-freetext" href="http://susi.theochem.tuwien.ac.at/reg_user/faq/supercells.html">http://susi.theochem.tuwien.ac.at/reg_user/faq/supercells.html</a><br>
[4]
<a class="moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/Space_group#Table_of_space_groups_in_3_dimensions">https://en.wikipedia.org/wiki/Space_group#Table_of_space_groups_in_3_dimensions</a><br>
[5] <a class="moz-txt-link-freetext" href="http://xrayweb.chem.ou.edu/notes/symmetry.html">http://xrayweb.chem.ou.edu/notes/symmetry.html</a><br>
[6] <a class="moz-txt-link-freetext" href="http://chemistry.bd.psu.edu/jircitano/6symmetry.pdf">http://chemistry.bd.psu.edu/jircitano/6symmetry.pdf</a><br>
[7]
<a class="moz-txt-link-freetext" href="https://www.mindat.org/article.php/2721/Determining+Symmetry+of+Crystals%3A+An+Introduction+">https://www.mindat.org/article.php/2721/Determining+Symmetry+of+Crystals%3A+An+Introduction+</a><br>
[8]
<a class="moz-txt-link-freetext" href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg20318.html">https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg20318.html</a><br>
[9]
<a class="moz-txt-link-freetext" href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14836.html">https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14836.html</a><br>
[10]
<a class="moz-txt-link-freetext" href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16765.html">https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16765.html</a><br>
[11] <a class="moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/Garbage_in,_garbage_out">https://en.wikipedia.org/wiki/Garbage_in,_garbage_out</a><br>
[12] <a class="moz-txt-link-freetext" href="https://it.iucr.org/">https://it.iucr.org/</a><br>
[13]
<a class="moz-txt-link-freetext" href="https://www.cryst.ehu.es/cgi-bin/cryst/programs/subgrmag1_cell.pl">https://www.cryst.ehu.es/cgi-bin/cryst/programs/subgrmag1_cell.pl</a><br>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">On 7/24/2020 6:55 PM, Peeyush Kumar
Kamlesh wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CA+o1xQeoVjbYg0Ph=CCgpWN3VZkb7MvKMDUZZtMXhYX19bezoA@mail.gmail.com">
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<div>Sir,</div>
<div>One more question. How can I know the space group of the
supercell? I searched but was unable to find it.<br>
</div>
<div>Thank you!<br>
</div>
</div>
</blockquote>
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