[CP2K-user] [CP2K:13056] COF cell optimize exploded
hut... at chem.uzh.ch
hut... at chem.uzh.ch
Mon Apr 6 07:32:46 UTC 2020
Hi
I assume your system is weakly bound in z-direction. Small force
changes in that direction can cause large changes.
The only obvious problem I could spot is the definition of the
reference cell. In order to minimize the effect of a change in
volume, the reference cell should be larger than the initial
and final cell. I would set c=10 or 12 and I would also increase
the cutoff.
You could test this by just scan the energy as function of c and
correctly adapt the geometry of course.
regards
Juerg Hutter
--------------------------------------------------------------
Juerg Hutter Phone : ++41 44 635 4491
Institut für Chemie C FAX : ++41 44 635 6838
Universität Zürich E-mail: hut... at chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
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-----cp... at googlegroups.com wrote: -----
To: "cp2k" <cp... at googlegroups.com>
From: "Linfeng Gan"
Sent by: cp... at googlegroups.com
Date: 04/05/2020 04:27AM
Subject: [CP2K:13056] COF cell optimize exploded
Hello all,
I need some help about the covalent-organic frameworks (COF) 2D sheet cell optimize. After I optimized the COF with a 2X2X2 supercell, the cell size was totally exploded. I had kept the cell vectors and symmetry constant, changed different basis sets and different XC functions but the cell exploded anyway.
I had tried basis sets DZVP-MOLOPT-GTH and DZVP-MOLOPT-SR-GTH with PADE, PBE and BLYP. And the DFTD3 correction was also add to each calculation. The GAPW method I also had tried, but none of them worked.
Any suggestion is welcome, thanks!
Linfeng
The COF-5-2X2X2 supercell vectors should be:
CELL_TOP| Volume [angstrom^3]: 21253.270
CELL_TOP| Vector a [angstrom 60.040 0.000 0.000 |a| = 60.040
CELL_TOP| Vector b [angstrom -30.020 51.996 0.000 |b| = 60.040
CELL_TOP| Vector c [angstrom 0.000 0.000 6.808 |c| = 6.808
CELL_TOP| Angle (b,c), alpha [degree]: 90.000
CELL_TOP| Angle (a,c), beta [degree]: 90.000
CELL_TOP| Angle (a,b), gamma [degree]: 120.000
But after cell optimized calculation the output cell vectors are:
*******************************************************************************
*** GEOMETRY OPTIMIZATION COMPLETED ***
*******************************************************************************
Reevaluating energy at the minimum
CELL| Volume [angstrom^3]: 25653.623
CELL| Vector a [angstrom]: 60.345 0.000 0.000 |a| = 60.345
CELL| Vector b [angstrom]: -30.173 52.260 0.000 |b| = 60.345
CELL| Vector c [angstrom]: 0.000 -0.000 8.135 |c| = 8.135
CELL| Angle (b,c), alpha [degree]: 90.000
CELL| Angle (a,c), beta [degree]: 90.000
CELL| Angle (a,b), gamma [degree]: 120.000
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[attachment "COF-5-2X2X2.xyz" removed by Jürg Hutter/at/UZH]
[attachment "opt_cell.inp" removed by Jürg Hutter/at/UZH]
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