<div dir="ltr">Dear Y. M. Qian,<br>you may try to reduce alpha_mix to 0.3/0.4 and restart your calculation, because if you use a very high value of alpha_mix and you are near the minima, it may be possible that that the new potential overshoot the minimum.<br>
<br>Prasenjit.<br><br><div class="gmail_quote">2008/10/6 yumin qian <span dir="ltr"><<a href="mailto:yuminqian@gmail.com">yuminqian@gmail.com</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div dir="ltr"><div> I did a phonon calculation with the A-spin type CaCrO3 system , the system is Pbnm structure , in the unit cell there are 20 atoms and the Cr atoms are spin parallel in a-b plane and anti-parallel along c axis .</div>
<div>After a scf calculation by pw.x whit a k-point mesh of 6 I choose a q point mesh of 4 but the thresh cann't be reached and ddv_scf|^2 dangling around 1.0E-7 ,I use the alpha_mix = 0.700 , how to make it converge for such large system?<br clear="all">
<br>-- <br>Sincerely Y. M. Qian <br>Lab.of Condensed Matter Theory and Materials Computation <br>Institute of Physics <br>Chinese Academy of Sciences<br>Tel: + 8610 8264 9147<br><a href="mailto:E-Mail%3Ayuminqian@gmail.com" target="_blank">E-Mail:yuminqian@gmail.com</a> <br>
P.O.Box 603 Beijing 100190<br>China <br><br></div></div>
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