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<p>Hi, <br>
</p>
<p><br>
</p>
<p>you can run a first geometry optimization run with a lower
EPS_SCF so that it converges faster to an approximate solution.
Once you are there you can restart with a tighter threshold. As
for the initial position of the molecules, I am not familiar with
your system myself, I am afraid.</p>
<p><br>
</p>
<p>Best,</p>
<p>Augustin<br>
</p>
<div class="moz-cite-prefix">On 2/8/20 3:20 PM, coko312 wrote:<br>
</div>
<blockquote type="cite"
cite="mid:0c081a4b-40b1-42...@googlegroups.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">Thank you very much both of you for these answers!
<div><br>
</div>
<div>Indeed I can reduce the size of my box to 10 Angstroms ;
for one Na+ ion and a CO2 molecule, I need to use 12
Angstroms. So I am confident now that nothing is crazy with my
simulation, but I guess I need a little more computing power
and parallel simulations.
<div><br>
</div>
<div>For a single Na+ ion, it works also very well with lower
EPS_SCF (1.E-8). However, with this EPS_SCF I have some
difficulties in making the SCF cycle converge with one Na+
ion and a CO2 molecule. I suspect it is due to the initial
position of my CO2 molecule. What would you use as a
reasonable distance/orientation, and how many iterations of
the geometry optimization procedure would you expect (50,
100, 500 ... )? </div>
<div>
<div><br>
</div>
<div><br>
<br>
Le lundi 27 janvier 2020 09:02:14 UTC+1, coko312 a écrit :
<blockquote class="gmail_quote" style="margin:
0;margin-left: 0.8ex;border-left: 1px #ccc
solid;padding-left: 1ex;">
<div dir="ltr">Dear all,
<div><br>
</div>
<div>I am a cp2k-DFT beginner so the answer to this
question may seem obvious to you, but it would help
me a lot!</div>
<div><br>
</div>
<div>I try to converge the total energy of a single
Na+ ion as a function of the energy CUTOFF, but the
convergence is very slow and even using 900 Ry is
not fully satisfactory for what I want to do. Even
with no experience with this system, I would not
expect the computation to last several hours on a
single processor for only 1 atom. I have attached my
input-output files. What should I modify to be able
to use a more reasonable CUTOFF? </div>
<div><br>
</div>
<div>NB : the computation is non-periodic because I
would like, next, to add more atoms around to
compute interaction energies between these little
"clusters" and various types of molecules.</div>
<div><br>
</div>
<div>Best,</div>
</div>
</blockquote>
</div>
</div>
</div>
</div>
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<pre class="moz-signature" cols="72">--
Augustin Bussy
PhD Student
--------------------------
University of Zurich
Augustin Bussy
Department of Chemistry
Research Group Hutter
Winterthurerstrasse 190
CH-8057 Zurich
Tel: +41 44 635 4490
<a class="moz-txt-link-abbreviated" href="http://www.chem.uzh.ch">www.chem.uzh.ch</a>
<a class="moz-txt-link-abbreviated" href="mailto:august...@chem.uzh.ch">august...@chem.uzh.ch</a>
--------------------------
</pre>
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