Very high forces on (experimentaly) relaxed geometries

Daniele Fontanari danielef... at gmail.com
Mon Nov 14 09:37:16 CET 2016


Thanks,

I thought about that but I checked only overlapping between As-As and S-S, 
while it seems that there are As-S overlapping.

Daniele

Il giorno lunedì 14 novembre 2016 09:24:02 UTC+1, Matt W ha scritto:
>
> Hi,
>
> I'd suggest you double,triple, quadruple check your cell parameters and 
> geometry before anything else. It seems to me likely that somehow you have 
> ovelapping atoms in periodic images.
>
> Matt
>
> On Sunday, November 13, 2016 at 6:32:02 PM UTC, Daniele Fontanari wrote:
>>
>> 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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