Cut-off problrm

[Matt W]

To see really clean convergence you need to turn off multigrids (set ngrids 
1).

Your set up is converged at the lowest setting you report.

We need a new tutorial on how to get happy pw settings.

On Monday, April 23, 2018 at 11:38:03 AM UTC+1, simin pahlavi wrote:
>
> Dear aal,
> Hello. 
> I am trying to find a suitable cutoff for my DFT calculation on 
> hydrocarbons according to the cp2k manual 
> https://www.cp2k.org/howto:converging_cutoff. I appriciate any help in 
> advance.
> The results never converge  and the calculated output for  REL_CUTOFF = 
> 60, is as following:
>   
> # Grid cutoff vs total energy
> # Date: Fri Apr 20 20:39:04 CEST 2018
> # PWD: /u/nsaf/JOBS/Ad-Ml.1/Cutoff-test
> # REL_CUTOFF = 60
> # Cutoff (Ry) | Total Energy (Ha) | NG on grid 1 | NG on grid 2 | NG on 
> grid 3 | NG on grid 4
>  800.0                   -231.7994673423      73445   28476     128       0
>  850.0                   -231.7994673423       73445   28476     128      
>  0
>  900.0                   -231.8023753152       69162   25725    7162      
>  0
>  950.0                   -231.8023753152       69162   25725    7162      
>  0
> 1000.0                  -231.8065368280       69162   25725    7162       0
> 1050.0                  -231.8065368280       69162   25725    7162       0
> 1100.0                  -231.8065368280       67054   27833    7162       0
> 1150.0                  -231.8129239556        67054   22834   12161      
>  0
> 1200.0                  -231.8129239556        67054   22834   12161      
>  0
> 1250.0                  -231.8129239556        67054   22834   12161      
>  0
> 1300.0                  -231.8129239556        66339   23501   12209      
>  0
> 1350.0                  -231.8129239556        66339   23501   12161      
> 48
> 1400.0                  -231.8148206637        66259   22420   13322      
> 48
> 1450.0                  -231.8148206637       66211   22468   13322      48
> 1500.0                  -231.8148206637        66211   22468   13322      
> 48
> 1550.0                  -231.8158559068        63323   25356   13322      
> 48
> 1600.0                  -231.8175292623        57217   31462   13322      
> 48
>
> ********************************************************************************
> Also my input file is :
>
> ******************************************************************************
> &GLOBAL
>  PRINT_LEVEL MEDIUM
> # WALLTIME 36:00:00  # changed
>  PROJECT cuttoff-test
>  RUN_TYPE ENERGY
>  SEED 300
> &END GLOBAL
>
>
> &FORCE_EVAL
>  METHOD Quickstep
>  &DFT
>   BASIS_SET_FILE_NAME ../data/BASIS_MOLOPT
>   POTENTIAL_FILE_NAME ../data/GTH_POTENTIALS
>     CHARGE 0
>     MULTIPLICITY 1
>     &MGRID
>   NGRIDS 4
>   CUTOFF LT_cutoff
>   REL_CUTOFF LT_rel_cutoff
>     &END
>    &QS
>       EPS_DEFAULT 1.0E-10
>       WF_INTERPOLATION PS
>       EXTRAPOLATION_ORDER 3
>       METHOD GPW
>     &END
>
>   &SCF
>    SCF_GUESS ATOMIC
>    EPS_SCF 5.e-7
>    MAX_SCF 1
>       &OT
>         MINIMIZER DIIS
>       &END OT
>    &OUTER_SCF
>     TYPE NONE
>     OPTIMIZER NONE
>     EPS_SCF 5.0E-7  
>     MAX_SCF 1
>    &END OUTER_SCF 
>   &END SCF
>
>   &XC
>    &XC_FUNCTIONAL PBE
>    &END XC_FUNCTIONAL
>    &XC_GRID
>     XC_SMOOTH_RHO NN50
>     XC_DERIV NN50_SMOOTH
>    &END XC_GRID
>    &VDW_POTENTIAL 
>     DISPERSION_FUNCTIONAL PAIR_POTENTIAL
>     &PAIR_POTENTIAL
>      TYPE DFTD3
>      PARAMETER_FILE_NAME ../data/dftd3.dat
>      REFERENCE_FUNCTIONAL PBE
>      CALCULATE_C9_TERM TRUE
>      REFERENCE_C9_TERM TRUE
>      LONG_RANGE_CORRECTION TRUE
>      VERBOSE_OUTPUT TRUE
>      R_CUTOFF 15.0
>     &END PAIR_POTENTIAL 
>    &END VDW_POTENTIAL
>   &END XC
>  &END DFT
>
>  &SUBSYS
>   &CELL
>    ABC 16.0 16.0 16.0
>    PERIODIC XYZ
>   &END CELL
>
>     &KIND H
>       BASIS_SET DZVP-MOLOPT-SR-GTH-q1
>       POTENTIAL GTH-PBE-q1
>     &END
>
>     &KIND C
>       BASIS_SET DZVP-MOLOPT-SR-GTH-q4
>      POTENTIAL GTH-PBE-q4
>     &END KIND
>
>
>     &TOPOLOGY
>       COORDINATE XYZ
>       COORD_FILE_NAME ../data/structure 
>       CONNECTIVITY OFF
>     &END TOPOLOGY
>  &END SUBSYS
> &END FORCE_EVAL
>
>
>
>
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