<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt"><div><span>Yes, of course it has 4 independent particles. But my main problem is about the algorithm of periodic boundary condition in the code. You must introduce the shared atoms in the unit cell or not. I think the symmetry operators produce these positions automatically.</span></div><div></div><div> </div><div>With the Best Regards</div><div><br><br></div><div> Reza Behjatmanesh-Ardakani<br> Associate Professor of Physical Chemistry<br> Address:<br> Department of Chemistry,<br> School of Science,<br> Payame Noor University (PNU),<br> Ardakan,<br> Yazd,<br> Iran.<br> E-mails: <br> 1- reza_b_m_a@yahoo.com (preferred),<br> 2- behjatmanesh@pnu.ac.ir, <br> 3- reza.b.m.a@gmail.com.</div><div class="yahoo_quoted" style="display: block;"> <br> <br>
<div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div dir="ltr"> <font face="Arial" size="2"> On Wednesday, December 11, 2013 10:28 PM, Axel Kohlmeyer <akohlmey@gmail.com> wrote:<br> </font> </div> <div class="y_msg_container">On Wed, Dec 11, 2013 at 7:47 PM, Reza Behjatmanesh-Ardakani<br clear="none"><<a href="mailto:reza_b_m_a@yahoo.com" shape="rect" ymailto="mailto:reza_b_m_a@yahoo.com">reza_b_m_a@yahoo.com</a>> wrote:<br clear="none">> Suppose, we have a simple fcc unit cell. Do we need to introduce one<br clear="none">> particle position (original particle) or 14 particles (8 on corners and 6 on<br clear="none">> the faces). I think only originals needed. Other particles can be produced<br clear="none">> by symmetry operators.<br
clear="none"><br clear="none">nope.<br clear="none"><br clear="none">a fcc lattice has only one atom. that is in the *primitive* cell<br clear="none">(which is what QE uses). what you describe is the conventional cell,<br clear="none">which would be a simple cubic lattice but that would not have 14 atoms<br clear="none">but 4 atoms (1 in the corner and 3 in the faces, because the corners<br clear="none">are shared by 8 cells and the faces by 2).<br clear="none"><br clear="none">i suggest you re-read the chapters covering these topics in your<br clear="none">favorite book on crystallography to work this out.<br clear="none"><br clear="none">axel.<div class="yqt5585577403" id="yqtfd90702"><br clear="none">><br clear="none">> With the Best Regards<br clear="none">><br clear="none">><br clear="none">> Reza Behjatmanesh-Ardakani<br clear="none">> Associate Professor of Physical Chemistry<br clear="none">> Address:<br clear="none">>
Department of Chemistry,<br clear="none">> School of Science,<br clear="none">> Payame Noor University (PNU),<br clear="none">> Ardakan,<br clear="none">> Yazd,<br clear="none">> Iran.<br clear="none">> E-mails:<br clear="none">> 1- <a href="mailto:reza_b_m_a@yahoo.com" shape="rect" ymailto="mailto:reza_b_m_a@yahoo.com">reza_b_m_a@yahoo.com</a> (preferred),<br clear="none">> 2- <a href="mailto:behjatmanesh@pnu.ac.ir" shape="rect" ymailto="mailto:behjatmanesh@pnu.ac.ir">behjatmanesh@pnu.ac.ir</a>,<br clear="none">> 3- <a href="mailto:reza.b.m.a@gmail.com." shape="rect" ymailto="mailto:reza.b.m.a@gmail.com.">reza.b.m.a@gmail.com.</a><br clear="none">><br clear="none">><br clear="none">> On Wednesday, December 11, 2013 7:19 PM, Paolo Giannozzi<br clear="none">> <<a href="mailto:paolo.giannozzi@uniud.it" shape="rect" ymailto="mailto:paolo.giannozzi@uniud.it">paolo.giannozzi@uniud.it</a>> wrote:<br
clear="none">> On Wed, 2013-12-11 at 07:12 -0800, Reza Behjatmanesh-Ardakani wrote:<br clear="none">><br clear="none">>> 1- For preparing the input file, if you introduce a symmetry in your<br clear="none">>> input's structure, only original particles<br clear="none">>> should be defined in the input file. Is it right?<br clear="none">><br clear="none">> no: you need to supply all atoms in a unit cell.<br clear="none">><br clear="none">><br clear="none">> P.<br clear="none">><br clear="none">> --<br clear="none">> Paolo Giannozzi, Dept. Chemistry&Physics&Environment,<br clear="none">> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br clear="none">> Phone +39-0432-558216, fax +39-0432-558222</div><br clear="none">><br clear="none">><br clear="none">><br clear="none">><br clear="none">><br clear="none">> _______________________________________________<br
clear="none">> Pw_forum mailing list<br clear="none">> <a href="mailto:Pw_forum@pwscf.org" shape="rect" ymailto="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br clear="none">> <a href="http://pwscf.org/mailman/listinfo/pw_forum" target="_blank" shape="rect">http://pwscf.org/mailman/listinfo/pw_forum</a><br clear="none"><br clear="none"><br clear="none"><br clear="none">-- <br clear="none">Dr. Axel Kohlmeyer <a href="mailto:akohlmey@gmail.com" shape="rect" ymailto="mailto:akohlmey@gmail.com">akohlmey@gmail.com</a> <a href="http://goo.gl/1wk0" target="_blank" shape="rect">http://goo.gl/1wk0</a><br clear="none">International Centre for Theoretical Physics, Trieste. Italy.<div class="yqt5585577403" id="yqtfd63637"><br clear="none"></div><br><br></div> </div> </div> </div> </div></body></html>