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Thank you for your suggestions!<br>
I tried using a small mixing beta (0.1~0.2), and tried using
reasonable cutoff energies (ecutwfc=50, ecutrho=500), now the
convergence is much better than before (converged down to 10^-6 Ry).
<br>
Another question is, I can find ultra-soft and PAW pseudopotentials,
which one is better for spin-orbit calculations? I am using PBE XC
functional.<br>
<br>
best,<br>
Yun-Peng<br>
<br>
<div class="moz-cite-prefix">On 09/11/2015 08:08 PM, yuewen.fang
wrote:<br>
</div>
<blockquote cite="mid:55f36ce9.0582440a.59c71.6f82@mx.google.com"
type="cite">
<div style=""> Dear Yun-Peng,
<div><br>
</div>
<div>Plz try to decrease mixing and perform some convergence
tests for your cutoff energy to remove the oscillation of the
energy! In addition, this oscillation could also be caused by
the unreasonable smearing methods for metals.</div>
<div><br>
</div>
<div>Bests</div>
<div>Fang<br>
<br>
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0;border-top: 1px solid #ccc;" align="left">
<div><a moz-do-not-send="true"
href="http://www.yomail.com/?utm_source=signature"
style="font-size:12pt;">Sent from YoMail</a></div>
<br>
<div class="gmail_quote"> <span dir="ltr">< <a
moz-do-not-send="true"
href="mailto:petercybertron@gmail.com" target="_blank">Peter
Cybertron</a>> 2015-09-12 03:10:31 wrote: </span> <br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr"> Hi,<br>
<br>
<br>
I am working in University of Florida as a postdoc.<br>
I am exploring the spin-orbital calculations using
pwscf, and I <br>
encounter a very slow convergence like this:<br>
> grep estimated scf.out<br>
estimated scf accuracy < 0.00000004 Ry<br>
... (100 similar lines)<br>
estimated scf accuracy < 0.00000003 Ry<br>
> grep "total energy" scf.out<br>
...<br>
total energy = -3667.91077719 Ry<br>
total energy = -3667.91078176 Ry<br>
total energy = -3667.91077642 Ry<br>
total energy = -3667.91078300 Ry<br>
<br>
<br>
Although the convergence of total energy seems OK (down
to 0.00001 Ry ~ <br>
0.0001 eV = 0.1 meV), I still feel uncomfortable since I
never encounter <br>
such a problem without spin-orbit interactions.<br>
<br>
<br>
I downloaded the ultrasoft and PAW pseudopotentials from
PSLib and I am <br>
using the PBE flavor of XC functional. The system I am
studying is a two <br>
dimensional magnetic insulator.<br>
<br>
<br>
The parameters I am using are:<br>
constrained_magnetization = 'total direction'<br>
fixed_magnetization(3) = 0.0<br>
lambda = 0.2<br>
ecutwfc = 30.0 ,<br>
ecutrho = 300.0 ,<br>
occupations = 'smearing' ,<br>
degauss = 0.005,<br>
smearing = 'mv' ,<br>
nosym=.true.<br>
mixing_mode = 'local-TF' ,<br>
mixing_beta = 0.9 ,<br>
diagonalization = 'david' ,<br>
<br>
<br>
Which parameter on earth keep my calculations
non-converged?<br>
<br>
<br>
Best,<br>
Yun-Peng<br>
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