<html><head></head><body><div class="ydpaadc0272yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div></div>
<div><br></div><div><br></div>
</div><div id="ydp906bfa77yahoo_quoted_9957802206" class="ydp906bfa77yahoo_quoted">
<div style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:13px;color:#26282a;">
<div>----- Forwarded Message -----</div>
<div><b>From:</b> David Kostov <dkca@yahoo.com></div><div><b>To:</b> users@lists.quantum-espresso.org <users@lists.quantum-espresso.org></div><div><b>Sent:</b> Tuesday, September 17, 2019, 3:00:06 p.m. CST</div><div><b>Subject:</b> fcc cell parameters</div><div><br></div>
<div><div id="ydp906bfa77yiv3913579513"><div><div class="ydp906bfa77yiv3913579513yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div dir="ltr">Dear QE users</div><div dir="ltr"><br></div><div dir="ltr">I am having a very basic question regading the way of defining the structure in QE. I am trying to understand the way of defining "cell parameter" section <span>when using the symmetry of the structure </span>in scf.in file of QE. <br></div><div dir="ltr"><br></div><div dir="ltr">For a fcc structure I saw in the pw.x definition that with ibrave=0 , we can define (I believe it is for primitive structure?)<br></div><div dir="ltr"><br></div><div dir="ltr">CELL_PARAMETER</div><div dir="ltr"><span><pre>a/2(-1,0,1) <br>a/2(0,1,1)<br>a/2(-1,1,0)</pre></span><div dir="ltr">My question is; can we also define this as below.</div><div dir="ltr"><div><span><pre>a/2(1,0,1) <br>a/2(0,1,1)<br>a/2(1,1,0)</pre></span></div><div dir="ltr">and does the order matters? ( I mean if I rotate this as below, does it requires any changes to the way I should give atomic positions? if so how to decide?)</div><div dir="ltr"><br></div><div dir="ltr"><span><span><pre>a/2(0,1,1)<br>a/2(1,0,1) <br>a/2(1,1,0)<br><br>Thank you<br>D.<br></pre></span></span></div><div dir="ltr"><div><span></span></div><div><br></div></div></div></div></div></div></div></div>
</div>
</div></body></html>