events:2018_summer_school:scf_setup
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Sensible SCF setups
SCF
The Kohn-Sham equations are non-linear. The potential changes as we optimise the Molecular Orbitals.
In this exercise we will explore a few of the options available to get a fast and robust optimisation for most systems.
Traditional Diagonalisation (TD)
Here is a basic input for a periodic box of water including a SCF section suitable for TD:
- scf_basic.inp
&FORCE_EVAL METHOD QS &DFT BASIS_SET_FILE_NAME GTH_BASIS_SETS BASIS_SET_FILE_NAME BASIS_MOLOPT POTENTIAL_FILE_NAME POTENTIAL &MGRID CUTOFF 300 &END MGRID &QS EPS_DEFAULT 1.0E-12 &END QS &SCF SCF_GUESS ATOMIC # SCF_GUESS RESTART EPS_SCF 1.0E-7 &MIXING ALPHA 0.4 &END &END SCF &XC &XC_FUNCTIONAL Pade &END XC_FUNCTIONAL &END XC &END DFT &SUBSYS &CELL ABC 9.8528 9.8528 9.8528 &END CELL # 32 H2O (TIP5P,1bar,300K) a = 9.8528 &COORD O 2.280398 9.146539 5.088696 O 1.251703 2.406261 7.769908 O 1.596302 6.920128 0.656695 O 2.957518 3.771868 1.877387 O 0.228972 5.884026 6.532308 O 9.023431 6.119654 0.092451 O 7.256289 8.493641 5.772041 O 5.090422 9.467016 0.743177 O 6.330888 7.363471 3.747750 O 7.763819 8.349367 9.279457 O 8.280798 3.837153 5.799282 O 8.878250 2.025797 1.664102 O 9.160372 0.285100 6.871004 O 4.962043 4.134437 0.173376 O 2.802896 8.690383 2.435952 O 9.123223 3.549232 8.876721 O 1.453702 1.402538 2.358278 O 6.536550 1.146790 7.609732 O 2.766709 0.881503 9.544263 O 0.856426 2.075964 5.010625 O 6.386036 1.918950 0.242690 O 2.733023 4.452756 5.850203 O 4.600039 9.254314 6.575944 O 3.665373 6.210561 3.158420 O 3.371648 6.925594 7.476036 O 5.287920 3.270653 6.155080 O 5.225237 6.959594 9.582991 O 0.846293 5.595877 3.820630 O 9.785620 8.164617 3.657879 O 8.509982 4.430362 2.679946 O 1.337625 8.580920 8.272484 O 8.054437 9.221335 1.991376 H 1.762019 9.820429 5.528454 H 3.095987 9.107088 5.588186 H 0.554129 2.982634 8.082024 H 1.771257 2.954779 7.182181 H 2.112148 6.126321 0.798136 H 1.776389 7.463264 1.424030 H 3.754249 3.824017 1.349436 H 3.010580 4.524142 2.466878 H 0.939475 5.243834 6.571945 H 0.515723 6.520548 5.877445 H 9.852960 6.490366 0.393593 H 8.556008 6.860063 -0.294256 H 7.886607 7.941321 6.234506 H 7.793855 9.141028 5.315813 H 4.467366 9.971162 0.219851 H 5.758685 10.102795 0.998994 H 6.652693 7.917443 3.036562 H 6.711966 7.743594 4.539279 H 7.751955 8.745180 10.150905 H 7.829208 9.092212 8.679343 H 8.312540 3.218330 6.528858 H 8.508855 4.680699 6.189990 H 9.742249 1.704975 1.922581 H 8.799060 2.876412 2.095861 H 9.505360 1.161677 6.701213 H 9.920117 -0.219794 7.161006 H 4.749903 4.186003 -0.758595 H 5.248010 5.018415 0.403676 H 3.576065 9.078451 2.026264 H 2.720238 9.146974 3.273164 H 9.085561 4.493058 9.031660 H 9.215391 3.166305 9.749133 H 1.999705 2.060411 1.927796 H 1.824184 0.564565 2.081195 H 7.430334 0.849764 7.438978 H 6.576029 1.537017 8.482885 H 2.415851 1.576460 8.987338 H 2.276957 0.099537 9.289499 H 1.160987 1.818023 4.140602 H 0.350256 2.874437 4.860741 H 5.768804 2.638450 0.375264 H 7.221823 2.257514 0.563730 H 3.260797 5.243390 5.962382 H 3.347848 3.732214 5.988196 H 5.328688 9.073059 5.982269 H 5.007063 9.672150 7.334875 H 4.566850 6.413356 3.408312 H 3.273115 7.061666 2.963521 H 3.878372 7.435003 6.843607 H 3.884673 6.966316 8.283117 H 5.918240 3.116802 5.451335 H 5.355924 2.495093 6.711958 H 5.071858 7.687254 10.185667 H 6.106394 7.112302 9.241707 H 1.637363 5.184910 4.169264 H 0.427645 4.908936 3.301903 H 9.971698 7.227076 3.709104 H 10.647901 8.579244 3.629806 H 8.046808 5.126383 2.213838 H 7.995317 4.290074 3.474723 H 1.872601 7.864672 7.930401 H 0.837635 8.186808 8.987268 H 8.314696 10.115534 2.212519 H 8.687134 8.667252 2.448452 &END COORD &KIND H BASIS_SET DZVP-GTH POTENTIAL GTH-PADE-q1 &END KIND &KIND O BASIS_SET DZVP-GTH POTENTIAL GTH-PADE-q6 &END KIND &END SUBSYS &END FORCE_EVAL &GLOBAL PROJECT H2O-32 RUN_TYPE ENERGY PRINT_LEVEL MEDIUM &END GLOBAL
TASK
This uses a rather small BASIS_SET DVZP-GTH which is much too small for production runs.
Repeat the calculation using
BASIS_SET TZV2P-GTH BASIS_SET DZVP-MOLOPT-GTH BASIS_SET TZV2P-MOLOPT-GTH
You should change the basis set for each atomic type (kind) in each case.
Orbital Transformation (OT)
We can see the effect of changing to the OT method by simply changing the SCF section.
&SCF SCF_GUESS RESTART EPS_SCF 1.0E-06 MAX_SCF 20 &OT ON MINIMIZER DIIS PRECONDITIONER FULL_ALL ENERGY_GAP 0.001 &END OT &OUTER_SCF MAX_SCF 2 &END OUTER_SCF &END SCF
TASK
events/2018_summer_school/scf_setup.1529226559.txt.gz · Last modified: 2020/08/21 10:14 (external edit)