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Hello Dirk,<br>
<br>
Thank you for the files. I will have a careful look at them and give
them a try. I will test the MP2 method on my small crystal and see
if it gives the correct optimization.<br>
<br>
What bothers me with my systems is that it is not only the crystal
which is expending but also the inter atomic distance, by which I
mean, the distance between two atoms that are part of the same
molecule. For example, the N-H bond length of the -NH3+ group of my
glycine molecule increases from 0.98 A to 1.4 A, at the point where
I stopped the calculation. It feels like there is a problem with the
input coordinates or that they are understood by cp2k as been in
Bohr whereas they are in Angstrom.<br>
<br>
Thanks again,<br>
Pierre<br>
<br>
<div class="moz-cite-prefix">On 08/08/2019 07:01, Dr. Dirk
Buddensiek wrote:<br>
</div>
<blockquote type="cite"
cite="mid:277971b0-6874-43...@googlegroups.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">
<div>Good morning Pierre,</div>
<div>please find enclosed an example which at least worked for
computation of the unit cell of
p-Dimethylaminothiopivalophenone. Unfortunately the
Online-Manual of CP2K is not self-explanatory. But there is a
lot of material (Tutorials, Excercises from summer Schools
etc.) available which might help.</div>
<div>Hope you succeed with the input file. Don´t worry. I had
some similar experience in the beginning.</div>
<div>Kind regards </div>
<div>Dirk</div>
<div>PS: In really difficult cases I guess Juerg Hutter and / or
Marcella Ianuzzi can help.</div>
<br>
Am Mittwoch, 7. August 2019 17:05:56 UTC+2 schrieb Pierre-André
Cazade:
<blockquote class="gmail_quote" style="margin: 0;margin-left:
0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;">
<div dir="ltr">Hello,
<div><br>
</div>
<div>I am rather new to CP2K though I am experienced with
molecular modelling both quantum and classical, and with a
wide range of software. It is quite frustrating that it
seems impossible to get CP2K to perform a simple CELL_OPT
of a beta glycine crystal (20 atoms, monoclinic) with PBE.
Such a calculation works fine with VASP, so I am quite
surprised the same calculation goes astray with CP2K.
Basically, the B unit cell vector increases drastically up
to absurd values. Needless to say, this is a test system
as I wish to use CP2K for its linear scaling DFT to model
protein crystals. I have tried to play with CUTOFF and
REL_CUTOFF in the MGRID section up to 1400 and 80
respectively. I also tried GPW and GAPW methods, all
electrons or GTH pseudo. Nothing works. Please, if anyone
could have a look at the attached input file
"cell_opt_qm.inp" and point what's wrong in it, I would be
grateful.</div>
<div><br>
</div>
<div>Furthermore, I have tried LS approach with DFTB on a
5x5x5 crystal of beta glycine and do not have much more
success. First, the pressure in the crystal is insanely
high and will lead again to a 20 folds increase of the
lattice vectors (with CG). Then, with LBFGS method, the
system stops after 3 to 4 cycles with a message telling
LBFGS convergence criteria were reached, whereas the
system is clearly not. Again, I would be grateful if
anyone could tell me what's wrong with my system
("cell_opt2_qm.inp" with "betacry.pdb" for the
coordinates). Ideally, my goal would be to be able to run
large complex systems with the LS approach and with any
DFT/DFTB method.</div>
<div><br>
</div>
<div>Thank you in advance for your help.</div>
<div><br>
</div>
<div>Regards,</div>
<div>Pierre</div>
</div>
</blockquote>
</div>
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<br>
<pre class="moz-signature" cols="72">--
Dr Pierre Cazade, PhD
AD3-023, Bernal Institute,
University of Limerick,
Plassey Park Road,
Castletroy, co. Limerick,
Ireland</pre>
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