[CP2K-user] [CP2K:13100] SCAN XC density functional: Do we have to use specific PSEUDOPOTENTIALS for SCAN? Are they available?

[Vyacheslav Bryantsev]

Dear Juerg and All,

Here I provide an update for a large band gap system, consisting of Mg2+ 
and Cl- ions (molten salt).  
Very high CUTOFF 2300 and REL_CUTOFF 100 were necessary to get converged 
SCF results with SCAN-D3 XC, suitable for MD. 
Using lower cutoffs, such as  CUTOFF 2000 and REL_CUTOFF 100 were not 
sufficient, because it required more > 100 SCF steps for some fraction of 
MD steps, which is not acceptable. Because of that, the average time for 
AIMD was higher than for the case with CUTOFF 2300.

The portion of used input file is shown below. The average time for each 
SCF step is 5-6 times slower compared to PBE-D3. 
Is this the expected behavior? Are there any ways I can explore to speed up 
SCAN-D3 calculations, used in the context of AIMD.

Thank you,
Slava

    &MGRID

      CUTOFF 2300

      REL_CUTOFF 100

!      NGRIDS 4

    &END MGRID

    &SCF

      MAX_SCF     150

      EPS_SCF     3.5E-6

      SCF_GUESS   RESTART

      &OUTER_SCF

        EPS_SCF 3.5E-6

        MAX_SCF 40

      &END

      &OT T

        MINIMIZER         CG

        PRECONDITIONER    FULL_ALL

      &END OT

    &END SCF

     &XC

       &XC_FUNCTIONAL

         &LIBXC

          FUNCTIONAL MGGA_X_SCAN

         &END LIBXC

         &LIBXC

           FUNCTIONAL MGGA_C_SCAN

          &END LIBXC

       &END XC_FUNCTIONAL

      &vdW_POTENTIAL

        DISPERSION_FUNCTIONAL PAIR_POTENTIAL

        &PAIR_POTENTIAL

           R_CUTOFF 40.0

           TYPE DFTD3

           D3_SCALING 1.0 1.324 0.0

           PARAMETER_FILE_NAME            dftd3.dat

!           REFERENCE_FUNCTIONAL SCAN

        &END PAIR_POTENTIAL

      &END vdW_POTENTIAL

    &END XC

  &END DFT


  &SUBSYS

    &CELL

      ABC                          24.450 24.450 24.450

      PERIODIC                     XYZ

    &END CELL

    &TOPOLOGY

      COORD_FILE_FORMAT XYZ

      COORD_FILE_NAME last_frame_wrapped.xyz

    &END TOPOLOGY

    &KIND Mg

      BASIS_SET DZVP-MOLOPT-SR-GTH

      POTENTIAL GTH-SCAN-q10

    &END KIND

    &KIND Cl

      BASIS_SET DZVP-MOLOPT-SR-GTH

      POTENTIAL GTH-SCAN-q7

    &END KIND

  &END SUBSYS

 

On Monday, April 13, 2020 at 10:09:19 AM UTC-4, Vyacheslav Bryantsev wrote:
>
> Dear Juerg and All,
>
> Thank you for recommendations.
> With regards to very high cutoffs, what should I try?
>
> I startred with CUTOFF 600 and REL_CUTOFF 100, and this does not seem to 
> work.
> Which setting would you recommends for SCAN XC?
>
> Thank you,
> Slava
>
>
>     &MGRID
>
>       CUTOFF 600
>
>       REL_CUTOFF 100
>
>     &END MGRID
>
>     &SCF
>
>       MAX_SCF     150
>
>       EPS_SCF     1.0E-6
>
>       SCF_GUESS   RESTART
>
>       &OUTER_SCF
>
>         EPS_SCF 1.0E-6
>
>         MAX_SCF 40
>
>       &END
>
>       &OT T
>
>         MINIMIZER         CG
>
>         PRECONDITIONER    FULL_ALL
>
>       &END OT
>
>
>
> On Friday, April 10, 2020 at 6:31:42 AM UTC-4, jgh wrote:
>>
>> Hi 
>>
>> 1) Many people have used PBE pp previously. 
>>    SCAN optimized pp can be found at 
>>    https://github.com/juerghutter/GTH/blob/master/SCAN/POTENTIAL 
>> 2) Newly published SCAN parameters for D3 are available in the current 
>>    version of CP2K from Github. For older version you need to 
>>    add a line in the input with the parameters. 
>> 3) Use very high cutoffs, depending on your system. If the cutoff is not 
>>    high enough SCF will not converge smoothly to a low value (10^-7 in 
>> OT). 
>>    I don't have experience if the smoothing methods work to reduce the 
>> cutoff. 
>>
>> regards 
>>
>> Juerg Hutter 
>> -------------------------------------------------------------- 
>> Juerg Hutter                         Phone : ++41 44 635 4491 
>> Institut für Chemie C                FAX   : ++41 44 635 6838 
>> Universität Zürich                   E-mail: h... at chem.uzh.ch 
>> Winterthurerstrasse 190 
>> CH-8057 Zürich, Switzerland 
>> --------------------------------------------------------------- 
>>
>> -----c... at googlegroups.com wrote: ----- 
>> To: "cp2k" <c... at googlegroups.com> 
>> From: "Vyacheslav Bryantsev" 
>> Sent by: c... at googlegroups.com 
>> Date: 04/09/2020 04:50PM 
>> Subject: [CP2K:13100] SCAN XC density functional: Do we have to use 
>> specific PSEUDOPOTENTIALS for SCAN? Are they available? 
>>
>> Dear CP2K Community, 
>>
>> Is there a set or recommended setting for using SCAN in cp2k? 
>>
>> More specifically, 
>> 1. Can we use PBE pseudopotentials for SCAN or this is a bad idea? If 
>> not, where one can find specific pseudopotentials reparametrized for SCAN? 
>> 2. Does the D3 correction work automatically now with SCAN. If not, how 
>> to specify it? 
>> 3. Recommendations for grid when using SCAN 
>>
>> Thank you, 
>> Slava   
>>
>>
>>   
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>>
>>   
>>
>
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