Very high forces on (experimentaly) relaxed geometries
Daniele Fontanari
danielef... at gmail.com
Sun Nov 13 19:32:02 CET 2016
Dear CP2K users
I'm very new to the software and DFT in general.
Hope this is the right place to ask this question.
I'd like to use CP2K to find structures of solids through geometry
optimization runs.
I thought that a good strategy for preliminary calculations was to take a
known structure (a crystal whose atom positions are known) and run a
geometry optimization on it.
My hope would be that it is possible to judge the "goodness" of the used
parameters by finding a relaxed structure close to the experimental.
I tried to work with As2S3 (on a cell counting 8 atoms of As and 12 atoms
of S). My first optimization run managed to decrease a lot the energy but
completely destroyed the structure of the molecule, to understand what is
going on I tried to compute the forces on the atoms in my experimental
configuration and it appears that the total force is close to 0, the forces
on almost all the atoms are close to 0 except on 2 couples As As and S S
where there are enormous (but with 0 resultant) forces. Might this be an
anomaly source of the issue?
Is there someone that can help me? Did I use bad potentials/basis/xc
functional? Not fine enough grids? bad scf algorithms for this system?
Thanks in advance.
Here it is the cp2k code, I tried to keep it simple, a thing might be
useful to know is that without the OT method the SCF run oscillates and
apparently doesn't converge.
&GLOBAL
PROJECT As2S3_forces_calc
RUN_TYPE ENERGY_FORCE
PRINT_LEVEL LOW
&END GLOBAL
&FORCE_EVAL
METHOD QS
&SUBSYS
&CELL
ABC 11.475 9.577 4.256
ALPHA_BETA_GAMMA 90.0 90.68 90.0
&END CELL
&TOPOLOGY
COORD_FILE_FORMAT XYZ
COORD_FILE_NAME As2S3.xyz
&END TOPOLOGY
&KIND S
BASIS_SET TZV2P-GTH
POTENTIAL GTH-PADE
&END KIND
&KIND As
BASIS_SET TZV2P-MOLOPT-SR-GTH
POTENTIAL GTH-PADE
&END KIND
&END SUBSYS
&DFT
BASIS_SET_FILE_NAME BASIS_MOLOPT_UCL
BASIS_SET_FILE_NAME GTH_BASIS_SETS
POTENTIAL_FILE_NAME GTH_POTENTIALS
&SCF
SCF_GUESS RESTART
MAX_SCF 500
&OT .TRUE.
&END OT
&END SCF
&XC
&XC_FUNCTIONAL PADE
&END XC_FUNCTIONAL
&END XC
&END DFT
&PRINT
&FORCES ON
&END FORCES
&END PRINT
&END FORCE_EVAL
MY_BASIS_SETS is generated by
$ cat GTH_BASIS_SETS BASIS_MOLOPT_UCL > MY_BASIS_SET
As2S3.xyz:
20
As2S3 (A,B,C)=(11.475 A, 9.577 A, 4.256 A)
(alpha,beta,gamma)=(90.0°,90.68°,90.0°)
As -2.87968 3.78519 -1.78703
As -6.29671 8.38345 4.62715
As -7.89374 4.70768 1.81738
As -1.28266 7.46095 1.02274
As -4.79404 4.29440 1.17991
As -4.38236 7.87423 1.66021
As -10.88155 5.01715 -0.01930
As 1.70516 7.15148 2.85942
S -4.38840 2.75627 -0.40167
S -4.78799 9.41236 3.24179
S -9.07372 4.85434 3.77704
S -0.10268 7.31429 -0.93692
S -2.91319 3.98145 2.45383
S -6.26321 8.18718 0.38629
S -9.35548 3.43549 0.63482
S 0.17909 8.73314 2.20530
S -0.92786 3.77410 -0.59081
S -8.24854 8.39453 3.43094
S -6.41721 2.99693 2.18326
S -2.75919 9.17170 0.65686
the output (minus the SFC run and the timing informations) (look at atoms
1-2 and 13-14!):
DBCSR| Multiplication driver
XSMM
DBCSR| Multrec recursion
limit 512
DBCSR| Multiplication stack size
1000
DBCSR| Maximum elements for images
UNLIMITED
DBCSR| Multiplicative factor virtual
images 1
DBCSR| Randmat seed
12341313
DBCSR| Multiplication size
stacks 3
DBCSR| Number of 3D layers
SINGLE
DBCSR| Use MPI memory
allocation T
DBCSR| Use RMA
algorithm F
DBCSR| Use Communication
thread T
DBCSR| Communication thread
load 87
**** **** ****** ** PROGRAM STARTED AT 2016-11-13
18:55:20.125
***** ** *** *** ** PROGRAM STARTED ON pinco.pallino
** **** ****** PROGRAM STARTED BY
fontanar
***** ** ** ** ** PROGRAM PROCESS ID
92218
**** ** ******* ** PROGRAM STARTED IN /home/fontanar/
CP2K| version string: CP2K version 5.0 (Development
Version)
CP2K| source code revision
number:
CP2K| cp2kflags: libint fftw3 libxc parallel mpi3 scalapack libxsmm
libgrid lib
CP2K| deriv_max_am1=6 libint_max_am=8
CP2K| is freely available from
https://www.cp2k.org/
CP2K| Program compiled at sam. nov. 5 22:37:09 CET
2016
CP2K| Program compiled on pinco.pallino
CP2K| Program compiled for impi
CP2K| Data directory path
/home/fontanar/cp2k/data
CP2K| Input file name
As2S3_forces.inp
...
...
...
Electronic density on regular grids: -111.9999999385
0.0000000615
Core density on regular grids: 111.9999999829
-0.0000000171
Total charge density on r-space grids: 0.0000000444
Total charge density g-space grids: 0.0000000444
Overlap energy of the core charge distribution:
92.65065405538122
Self energy of the core charge distribution:
-398.65263980352455
Core Hamiltonian energy:
105.34301297451202
Hartree energy:
196.75976380751200
Exchange-correlation energy:
-41.98461449052979
Total energy:
-45.88382345664910
ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):
-45.883823518851351
ATOMIC FORCES in [a.u.]
# Atom Kind Element X Y Z
1 1 As -18.30244796 -211.32223506 15.97738109
2 1 As 18.30955215 211.29826724 -15.97476790
3 1 As 0.03033974 -0.01535037 -0.02243601
4 1 As -0.03033573 0.01527827 0.02246948
5 1 As -0.06302510 -0.01399788 -0.06420679
6 1 As 0.06288169 0.01397371 0.06420477
7 1 As -0.14318658 0.03752386 0.05230394
8 1 As 0.14341018 -0.03742549 -0.05230464
9 2 S -0.04378316 -0.00438881 0.05507047
10 2 S 0.04393888 0.00437103 -0.05527078
11 2 S 0.15237734 0.06345576 -0.07781696
12 2 S -0.15250573 -0.06340104 0.07801514
13 2 S 18.35579677 211.32485524 -15.99099261
14 2 S -18.36294583 -211.30098802 15.98856882
15 2 S -0.00508091 -0.11845479 0.09971522
16 2 S 0.00502481 0.11846616 -0.09985495
17 2 S 0.00456838 -0.00974499 0.01222899
18 2 S -0.00470629 0.00972000 -0.01233881
19 2 S 0.00523795 0.02733833 -0.00734223
20 2 S -0.00512153 -0.02726010 0.00737305
SUM OF ATOMIC FORCES -0.00001092 0.00000307
-0.00000070 0.00001136
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