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Dear Forum,<br>
just in case this could be useful to anyone else in the future.<br>
<br>
The difference I found out, in spin polarized systems, between<br>
Born effective charges computed with "zue" and "zeu"<br>
was due to a low value of the threshold in the phonon<br>
calculation.<br>
<br>
I was using the default value of tr2_ph=1e-12.<br>
Setting tr2_ph=1e-14 the difference is much smaller (<1%).<br>
(for the pw run I used conv_thr=1.0d-8)<br>
<br>
Thanks to Paolo Giannozzi and Andrea Del Corso for the advices.<br>
<br>
Best regards,<br>
Davide<br>
<br>
On 03/24/2011 07:08 PM, Srijan Kumar Saha wrote:
<blockquote
cite="mid:AANLkTinMyKLrTWOVKnnD=EG1mZaqHfuNv82zkTbvi4DK@mail.gmail.com"
type="cite"> Dear Davide,<br>
<br>
If possible, please attach the input files as well for a quicker
and complete answer.<br>
<br>
regards,<br>
Srijan Kumar<br>
R&D Assistant <br>
JNCASR<br>
Bangalore 560064<br>
<br>
<div class="gmail_quote">
On Thu, Mar 24, 2011 at 5:37 PM, Davide Sangalli <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:davide.sangalli@gmail.com">davide.sangalli@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<div bgcolor="#ffffff" text="#000000"> Dear Forum,<br>
<br>
I tried to use the ph code in order to compute Born
effective charges for a spin-polarized system.<br>
The results I've obtained from the "zue" and the "zeu"
methods are different.<br>
<br>
The values for the Fe atom in one case are positive and in
the other are negative.<br>
I've used the version of the code from the cvs repository<br>
(which was working properly for a non-polarized system.)<br>
<br>
Any suggestion?<br>
Attached the output of the two calculations and of the pwscf
run.<br>
<br>
Thank you and best regards,<br>
Davide<br>
<br>
</div>
</blockquote>
</div>
<br>
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