Pseudooptimization?

Ilya ikupc... at gmail.com
Tue Nov 17 18:11:32 CET 2009


Dear CP2K users.

I run into a problem few days ago.

I have performed a small (60 atoms) piece of hydrated quartz QS DFT
relaxation.

Cp2k could not find energy minimum at a time.

If I take optimized coordinates, put them in the input file again and
restart the optimization with the SCF_GUESS ATOMIC, cp2k will continue
optimization and will find some lower minimum.

The amount of opt steps needed to reach the minimum is much fewer. The
energy may differ by ~0.01 but in my case it really matters.

Launching 2-3 sequential optimizations I managed to find the exact
minimum value.

Anyway it looks suspicious. As it makes up a new wave function
approximation for an "optimized" coords the whole optimization goes in
a slightly different way each restart. As I got.

I tried to apply different optmizers - CG, BFGS, LBFGS. I also tried
to use OT, Mixing/Diag, changing SCF optimizers CG, DIIS. All those
influenced slightly. Still it does new optimization each restart,
instead of saing "nothing to do everything is optimized".

Now trying to change CUTOFF value, may be this could help.
The question might be stupid, I feel that the answer is simple, just
can't get it.

If someone have some ideas, I will appreciate you advice.

Input


 &GLOBAL
   PRINT_LEVEL  LOW
   PROJECT_NAME ps-t-11
   RUN_TYPE  GEO_OPT
   PREFERRED_FFT_LIBRARY FFTW
 &END GLOBAL
 &MOTION
   &GEO_OPT
     OPTIMIZER  CG
     MAX_DR 3.00000000E-04
     MAX_FORCE  4.50000000E-05
     RMS_DR    1.50000000E-04
     RMS_FORCE  3.00000000E-05
     MAX_ITER             1000
   &END GEO_OPT
 &END MOTION
 &FORCE_EVAL
   METHOD  QS
   &DFT
     BASIS_SET_FILE_NAME GTH_BASIS_SETS
     &SCF
       SCF_GUESS ATOMIC
       MAX_SCF            1000
     &END SCF
     &XC
       &XC_FUNCTIONAL  PBE
       &END XC_FUNCTIONAL
     &END XC
     &POISSON
       PERIODIC XZ
       POISSON_SOLVER WAVELET
     &END POISSON
   &END DFT
   &SUBSYS
     &CELL
      ABC     9.8724 25.0 10.08094
    UNITS  ANGSTROM
       PERIODIC  XZ
     &END CELL
     &KIND Si
       BASIS_SET TZVP-GTH
       POTENTIAL GTH-PBE-q4
     &END KIND
     &KIND O
       BASIS_SET TZVP-GTH
       POTENTIAL GTH-PBE-q6
     &END KIND
     &KIND C
       BASIS_SET TZVP-GTH
       POTENTIAL GTH-PBE-q4
     &END KIND
     &KIND B
       BASIS_SET TZVPP-GTH
       POTENTIAL GTH-PBE-q3
     &END KIND
     &KIND H
       BASIS_SET TZVP-GTH
       POTENTIAL GTH-PBE-q1
     &END KIND
     &TOPOLOGY
       COORD_FILE_FORMAT XYZ
       COORD_FILE_NAME /home/kupchenko/job/ps/t/ps.xyz
       CENTER_COORDINATES  T
     &END TOPOLOGY
   &END SUBSYS
 &END FORCE_EVAL

Coordinate file ps.xyz:

      60
 i =        1, E =      -570.7446060489
  H         1.2164405235       15.4842136302        0.4143744831
  H         6.1121896899       15.5038087647        0.4144334876
  H         1.2707602262       15.3655789278        5.4048093021
  H         6.1271079554       15.4026946050        5.4235580700
  O         0.4551586659       15.1183862048        0.9207263709
  O         5.3651001781       15.1154121407        0.9229189539
  O         0.5077183637       15.1235599574        5.9915222988
  O         5.3762635138       15.1158339064        6.0005346429
  H         3.8570937184       15.1545145022        5.1023747623
  H         8.8344418767       15.1584752804        5.0833260666
  H         3.8786236331       15.1947700953       10.3189982581
  H         8.8423420430       15.2102731172       10.2764809174
  O         3.0957286169       14.9472184410        4.5045744980
  O         8.0582595943       14.9554451515        4.5037182386
  O         3.0983543419       14.9962628173        9.7165567981
  O         8.0637432247       15.0292909929        9.6668423665
  O         2.4682398721       13.9468761359        2.1126453081
  O         7.4016859412       13.9535260868        2.1076981879
  O         2.4331459358       13.9452444285        7.4094370497
  O         7.3474209604       13.9487720010        7.3996943622
 Si         0.9174823157       13.6452453328        1.6331964708
 Si         5.8506776815       13.6460140438        1.6312922823
 Si         0.8945731285       13.7654223514        6.8801727781
 Si         5.8090768385       13.7639843442        6.8815442106
 Si         3.3445442865       13.6624717732        3.4584593898
 Si         8.2735277184       13.6625861281        3.4589630814
 Si         3.3211393429       13.6848373669        8.7566224332
 Si         8.2481557358       13.6840992310        8.7402594584
  O         4.9261822520       13.4850120463        3.0058435744
  O         9.8492612051       13.4823424700        2.9989183455
  O         4.8578563490       13.4964580997        8.1955274091
  O         9.7798690555       13.4911169759        8.1692673736
  O         0.8797033120       12.3830946804        0.6001141356
  O         5.7933420692       12.3831395817        0.6001632671
  O         0.8817757579       12.3795984391        6.0019735587
  O         5.7953154313       12.3796068132        6.0019844251
  O         2.7873912363       12.2645536217        4.1156930416
  O         7.7011498729       12.2647096129        4.1156209075
  O         2.8124720845       12.2891736146        9.5066763280
  O         7.7263380707       12.2894528459        9.5065558302
 Si         1.8767330997       11.4234259421       -0.2249206571
 Si         6.7904244881       11.4233716970       -0.2249530592
 Si         1.8906925923       11.4346717365        5.1661113227
 Si         6.8044045172       11.4346717256        5.1660918387
  O         2.8683800441       10.6886833092        0.8130047883
  O         7.7820554561       10.6886976079        0.8130092380
  O         2.8661225434       10.6907181430        6.2154513092
  O         7.7798155302       10.6907252061        6.2154563221
  O         0.9993480464       10.3826593668        4.3304611630
  O         5.9130553067       10.3826768100        4.3304808739
  O         0.9879650764       10.3694140533        9.7308331231
  O         5.9016086863       10.3694428080        9.7308465605
  H         2.5220936594        9.9015909978        1.2556566675
  H         7.4361354814        9.8984291273        1.2500346062
  H         3.8152371223       10.6874649056        5.9934984006
  H         8.7297691935       10.6932243995        5.9965260796
  H         1.3674986990        9.4962228514        4.1919909263
  H         6.2998681174        9.5107427878        4.1552631113
  H         0.0234329886       10.3965414804        9.7770309728
  H         4.9370093473       10.3979787214        9.7924189287



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