<div dir="ltr"><div dir="ltr">Quick google search: <a href="http://quantum.phys.cmu.edu/groupth/gt21.pdf">http://quantum.phys.cmu.edu/groupth/gt21.pdf</a><br></div></div><br><div class="gmail_quote"><div dir="ltr">On Fri, Jan 11, 2019 at 10:23 AM Offermans Willem <<a href="mailto:willem.offermans@vito.be">willem.offermans@vito.be</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div style="overflow-wrap: break-word;">
<div>Sorry for my ignorance, but I still don’t see the point.</div>
<div><br>
</div>
<div>Maybe a reference to some literature might help.</div>
<div><br>
</div>
<br>
<div>
<div dir="auto" style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
<div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
<div dir="auto" style="overflow-wrap: break-word;">
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
Met vriendelijke groeten,</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
Mit freundlichen Grüßen,</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
With kind regards,</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
<br>
</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
<br>
</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
Willem Offermans</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
Researcher Electrocatalysis SCT</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
VITO NV | Boeretang 200 | 2400 Mol</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
Phone:+32(0)14335263 Mobile:+32(0)492182073 </div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
<br>
</div>
<div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
<a href="mailto:Willem.Offermans@Vito.be" target="_blank">Willem.Offermans@Vito.be</a></div>
</div>
</div>
</div>
<span style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none"><br class="gmail-m_6435918764872608877Apple-interchange-newline" style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
<span style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none"><span><img id="gmail-m_6435918764872608877176B2E24-2115-4B77-8344-EE4FE577C84D" src="cid:1683cfc4764605dda611"></span>
</span></span></div>
<div><br>
<blockquote type="cite">
<div>On 11 Jan 2019, at 09:58, Malte Sachs <<a href="mailto:malte.sachs@chemie.uni-marburg.de" target="_blank">malte.sachs@chemie.uni-marburg.de</a>> wrote:</div>
<br class="gmail-m_6435918764872608877Apple-interchange-newline">
<div>
<div bgcolor="#FFFFFF">
<div class="gmail-m_6435918764872608877moz-cite-prefix">Dear Willem,</div>
<div class="gmail-m_6435918764872608877moz-cite-prefix"><br>
</div>
<div class="gmail-m_6435918764872608877moz-cite-prefix">in case of a screw axis or a glide plane you couple a rotation or a mirrow with a fractional translation (e.g. 1/2 or 1/3 of a lattice vector).</div>
<div class="gmail-m_6435918764872608877moz-cite-prefix"><br>
</div>
<div class="gmail-m_6435918764872608877moz-cite-prefix">Best,<br>
Malte<br>
</div>
<div class="gmail-m_6435918764872608877moz-cite-prefix"><br>
</div>
<div class="gmail-m_6435918764872608877moz-cite-prefix"><br>
</div>
<div class="gmail-m_6435918764872608877moz-cite-prefix">Am 11.01.2019 um 09:03 schrieb Offermans Willem:<br>
</div>
<blockquote type="cite">
<div>Dear Paolo and Quantum Espresso friends,</div>
<div><br>
</div>
<div>I’m sorry, but your explanation did not enlighten me. </div>
<div><br>
</div>
<div>Your response: "it means that the symmetry operation consists in a rotation (or a rotation + spatial inversion) plus a translation (not a lattice one)” don’t ring a bell. </div>
<div><br>
</div>
<div>What kind of translational symmetry are you talking about, if not the lattice one?</div>
<div><br>
</div>
<div>My system has S2-Symmetry. This means a rotation about 180<span style="color:rgb(34,34,34);font-family:sans-serif;font-size:14px;background-color:rgb(255,255,255)">°</span>, <span>followed
by reflection in a plane perpendicular to the rotation axis. It can be shortened to an inversion centre. Combined with the identity operation, this leads to 2 </span>Sym.Ops, which have been detected by the program. This is consistent with the message in the
output. Since I’m dealing with a slab, the system also has translational symmetry. I don’t see why the inversion centre should be incommensurate with this translational symmetry.</div>
<div><br>
</div>
<div>What is the connection to the FFT grid?</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div> </div>
<span><br>
</span><span>
<div>Met vriendelijke groeten,<br>
Mit freundlichen Grüßen,<br>
With kind regards,<br>
<br>
<br>
Willem Offermans<br>
Researcher Electrocatalysis SCT<br>
VITO NV | Boeretang 200 | 2400 Mol<br>
Phone:+32(0)14335263 Mobile:+32(0)492182073 <br>
<br>
<a href="mailto:Willem.Offermans@Vito.be" target="_blank">Willem.Offermans@Vito.be</a><br>
<span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none"><br class="gmail-m_6435918764872608877Apple-interchange-newline" style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none">
<span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none"><span><span id="gmail-m_6435918764872608877cid:part2.9861BE7F.B9B43AFE@chemie.uni-marburg.de"><vito.jpg></span></span>
</span></span><br>
</div>
</span>
<div><br>
<blockquote type="cite">
<div>On 10 Jan 2019, at 22:00, Paolo Giannozzi <<a href="mailto:p.giannozzi@gmail.com" target="_blank">p.giannozzi@gmail.com</a>> wrote:</div>
<br class="gmail-m_6435918764872608877Apple-interchange-newline">
<div>
<div dir="ltr">
<div dir="ltr">On Thu, Jan 10, 2019 at 4:30 PM Offermans Willem <<a href="mailto:willem.offermans@vito.be" target="_blank">willem.offermans@vito.be</a>> wrote:</div>
<div dir="ltr"><br>
</div>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<div>
<div> 2 Sym. Ops., with inversion, found ( 1 have fractional translation) </div>
[...] What does it mean?</div>
</div>
</blockquote>
<div><br>
</div>
<div>it means that the symmetry operation consists in a rotation (or a rotation + spatial inversion) plus a translation (not a lattice one)<br>
</div>
<div><br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<div>
<div>At some point in the sequence of calculations, the output contained the following message about symmetry:</div>
<div><br>
</div>
<div> No symmetry found</div>
<div><br>
</div>
<div>I was surprised about the lost of symmetry. Is it related to the fractional translation?</div>
</div>
</div>
</blockquote>
<div><br>
</div>
<div>no, unless this happens in the last scf step, in which the FFT grid may change, in which case this is what may happen:</div>
<div><br>
</div>
<div> (note: 1 additional sym.ops. were found but ignored
<div> their fractional translations are incommensurate with FFT grid)</div>
<div>Paolo<br clear="all">
</div>
</div>
</div>
-- <br>
<div dir="ltr" class="gmail-m_6435918764872608877gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">
<div>Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,<br>
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>
Phone +39-0432-558216, fax +39-0432-558222<br>
<br>
</div>
</div>
</div>
</div>
</div>
</div>
<span id="gmail-m_6435918764872608877cid:168398bf79c605dda611"><vito.jpg></span>_______________________________________________<br>
users mailing list<br>
<a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a><br>
<a class="gmail-m_6435918764872608877moz-txt-link-freetext" href="https://lists.quantum-espresso.org/mailman/listinfo/users" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></div>
</blockquote>
</div>
<br>
<font size="-2" face="Arial, Helvetica, sans-serif" color="#999999">Indien u VITO Mol bezoekt, hou aub er dan rekening mee dat de hoofdingang voortaan enkel bereikbaar is vanuit de richting Dessel-Retie, niet vanuit richting Mol, zie
<a href="http://www.vito.be/route" target="_blank">vito.be/route.</a><br>
If you plan to visit VITO at Mol, then please note that the main entrance can only be reached coming from Dessel-Retie and no longer coming from Mol, see
<a href="http://www.vito.be/en/contact/locations" target="_blank">
vito.be/en/contact/locations.</a><br>
</font><font size="-2" face="Arial, Helvetica, sans-serif" color="#999999">VITO Disclaimer:
<a href="http://www.vito.be/e-maildisclaimer" target="_blank"><font color="#999999">http://www.vito.be/e-maildisclaimer</font></a></font>
<br>
<br>
<fieldset class="gmail-m_6435918764872608877mimeAttachmentHeader"></fieldset>
<pre class="gmail-m_6435918764872608877moz-quote-pre">_______________________________________________
users mailing list
<a class="gmail-m_6435918764872608877moz-txt-link-abbreviated" href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a>
<a class="gmail-m_6435918764872608877moz-txt-link-freetext" href="https://lists.quantum-espresso.org/mailman/listinfo/users" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></pre>
</blockquote>
<p><br>
</p>
</div>
_______________________________________________<br>
users mailing list<br>
<a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a><br>
<a href="https://lists.quantum-espresso.org/mailman/listinfo/users" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></div>
</blockquote>
</div>
<br>
</div>
_______________________________________________<br>
users mailing list<br>
<a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a><br>
<a href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="noreferrer" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></blockquote></div><br clear="all"><br>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div>Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,<br>Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>Phone +39-0432-558216, fax +39-0432-558222<br><br></div></div></div></div></div>