<html dir="ltr">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body fpstyle="1" ocsi="0" bgcolor="#FFFFFF">
<div style="direction: ltr;font-family: Times New Roman;color: #000000;font-size: 10pt;">
Thanks for your reply but I am still not very sure I understand well the difference between the two options:<br>
'xy' : only v1_x and v2_y are moved<br>
'2Dxy' : only x and y components are allowed to change<br>
<br>
When the vectors v1 and v2 are not orthogonal (which is my case) the option 'xy' is not appropriate ?<br>
<br>
Cyrille<br>
<div><br>
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px"><font size="2">========================<br>
</font>
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px"><font size="2"></font>
<div style="font-family:Tahoma; font-size:13px"><font size="2"></font>
<div style="font-family:Tahoma; font-size:13px"><font size="2"></font>
<div style="font-family:Tahoma; font-size:13px"><b>Cyrille Barreteau</b><br>
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px"><font size="2"><font face="Times New Roman">CEA Saclay<span style="background-color:white"></span></font><font face="Times New Roman">,
</font><font face="Times New Roman"><font face="Times New Roman"><font face="Times New Roman">IRAMIS,</font> SPEC</font></font><font face="Times New Roman"><font face="Times New Roman"><span style="background-color:white"> Bat. 771<br>
</span></font>91191 Gif sur Yvette Cedex<span style="background-color:white"></span>, FRANCE
</font><br>
<font face="Times New Roman"><font face="Times New Roman">~~~~~~~~~~~~~~~~~~~~~~~~~~~~</font><br>
</font><font face="Times New Roman"><font face="Times New Roman"><font face="Times New Roman">+33 1 69 08 38 56 /</font></font></font><font face="Times New Roman"><font face="Times New Roman"><font face="Times New Roman"><font face="Times New Roman"><font face="Times New Roman">+33
6 47 53 66 52 (mobile) </font></font></font> </font></font></font><br>
<font face="Times New Roman">email: cyrille.barreteau@cea.fr </font><font face="Times New Roman"><br>
Web: <a href="http://iramis.cea.fr/Pisp/cyrille.barreteau/" tabindex="0">http://iramis.cea.fr/Pisp/cyrille.barreteau/</a></font><font size="2"><br>
</font><font size="2">========================</font></div>
</div>
</div>
</div>
<span style="background-color:white; font-family:Times New Roman"><font size="2" color="black"><span dir="ltr" style="font-size:10pt"><font size="2"><span style="font-size:16px"></span></font></span></font></span></div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div style="font-family: Times New Roman; color: #000000; font-size: 16px">
<hr tabindex="-1">
<div id="divRpF304973" style="direction: ltr;"><font size="2" color="#000000" face="Tahoma"><b>De :</b> pw_forum-bounces@pwscf.org [pw_forum-bounces@pwscf.org] de la part de Thomas Brumme [thomas.brumme@uni-leipzig.de]<br>
<b>Envoyé :</b> mardi 25 juillet 2017 11:32<br>
<b>À :</b> pw_forum@pwscf.org<br>
<b>Objet :</b> Re: [Pw_forum] vc-relax & cell_dofree<br>
</font><br>
</div>
<div></div>
<div>
<p>Dear Cyrille,</p>
<p><br>
</p>
<p>from the input description:<br>
<br>
'xy' : only v1_x and v2_y are moved<br>
<br>
'2Dxy' : only x and y components are allowed to change<br>
<br>
Thus, even in the case of cell_dofree='xy' I think the cell will change. Anyway, the deviation from 120 DEG is quite small (119.43 DEG if I'm not wrong) - I don't know if this could be do to numerical issues. Maybe try starting a new relaxation with a hexagonal
cell but smaller in-plane lattice vector of ~99.1%</p>
<p><br>
</p>
<p>Cheerio</p>
<p><br>
</p>
<p>Thomas<br>
</p>
<br>
<div class="moz-cite-prefix">On 07/25/17 09:08, BARRETEAU Cyrille wrote:<br>
</div>
<blockquote type="cite"><style type="text/css" id="owaParaStyle">
<!--
p
{margin-top:0;
margin-bottom:0}
-->
BODY {direction: ltr;font-family: Times New Roman;color: #000000;font-size: 10pt;}P {margin-top:0;margin-bottom:0;}BODY {scrollbar-base-color:undefined;scrollbar-highlight-color:undefined;scrollbar-darkshadow-color:undefined;scrollbar-track-color:undefined;scrollbar-arrow-color:undefined}</style>
<div style="direction:ltr; font-family:Times New Roman; color:#000000; font-size:10pt">
Dear QE community<br>
<br>
I have a question related to vc-relax and the option cell_dofree.<br>
I want to relax a 2D metal-organic framework (MOF) with hexagonal lattice (ibrav=4)<br>
Could you please explain what is the difference between cell-dofree=xy and cell_dofree=2Dxy?<br>
<br>
I have noticed that when using cell_dofree=2Dxy the final CELL_PARAMETER is no longer perfectly hexagonal (see below). Should I use cell_dofree=xy instead and why?<br>
<br>
final:<br>
CELL_PARAMETERS (alat= 25.44640422)<br>
0.990921488 -0.000187347 0.000000000<br>
-0.495622997 0.858299558 0.000000000<br>
0.000000000 0.000000000 0.742630080<br>
<br>
Thanks in advance<br>
<br>
Cyrille<br>
<div><br>
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px"><font size="2">========================<br>
</font>
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px"><b>Cyrille Barreteau</b><br>
<div style="font-family:Tahoma; font-size:13px">
<div style="font-family:Tahoma; font-size:13px"><font size="2"><font face="Times New Roman">CEA Saclay<span style="background-color:white"></span></font><font face="Times New
Roman">,
</font><font face="Times
New Roman"><font face="Times
New Roman"><font face="Times
New Roman">IRAMIS,</font>
SPEC</font></font><font face="Times
New Roman"><font face="Times
New Roman"><span style="background-color:white"> Bat. 771<br>
</span></font>91191 Gif sur Yvette Cedex<span style="background-color:white"></span>, FRANCE
</font><br>
<font face="Times
New Roman"><font face="Times
New Roman">~~~~~~~~~~~~~~~~~~~~~~~~~~~~</font><br>
</font><font face="Times
New Roman"><font face="Times
New Roman"><font face="Times
New Roman">+33
1 69 08 38 56 /</font></font></font><font face="Times
New Roman"><font face="Times
New Roman"><font face="Times
New Roman"><font face="Times
New Roman"><font face="Times
New Roman">+33
6 47 53 66 52 (mobile) </font></font></font> </font></font></font><br>
<font face="Times
New Roman">email:
<a class="moz-txt-link-abbreviated" href="mailto:cyrille.barreteau@cea.fr" target="_blank">
cyrille.barreteau@cea.fr</a> </font><font face="Times New Roman"><br>
Web: <a href="http://iramis.cea.fr/Pisp/cyrille.barreteau/" tabindex="0" target="_blank">
http://iramis.cea.fr/Pisp/cyrille.barreteau/</a></font><font size="2"><br>
</font><font size="2">========================</font></div>
</div>
</div>
</div>
<span style="background-color:white; font-family:Times
New Roman"><font size="2" color="black"><span dir="ltr" style="font-size:10pt"><font size="2"><span style="font-size:16px"></span></font></span></font></span></div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div style="font-family:Times New Roman; color:#000000; font-size:16px">
<hr tabindex="-1">
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader" target="_blank"></fieldset> <br>
<pre>_______________________________________________
Pw_forum mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Pw_forum@pwscf.org" target="_blank">Pw_forum@pwscf.org</a>
<a class="moz-txt-link-freetext" href="http://pwscf.org/mailman/listinfo/pw_forum" target="_blank">http://pwscf.org/mailman/listinfo/pw_forum</a></pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig
Tel: +49 (0)341 97 36456
email: <a class="moz-txt-link-abbreviated" href="mailto:thomas.brumme@uni-leipzig.de" target="_blank">thomas.brumme@uni-leipzig.de</a>
</pre>
</div>
</div>
</div>
</body>
</html>