[CP2K-user] [CP2K:13118] SCAN XC density functional: Do we have to use specific PSEUDOPOTENTIALS for SCAN? Are they available?

Vyacheslav Bryantsev vyachesla... at gmail.com
Mon Apr 13 19:01:31 UTC 2020

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Dear Thomas.

I am familiar with this tutorial. 
The purpose for having so high CUTOFF and REL_CUTOFF is not to get the 
converged results, but simply be able to converge SCF for consecutive MD 
steps.
For example,  using CUTOFF 1500 and  REL_CUTOFF  200 would give converged 
SCF cycles taking 1000s of steps for consecutive MD steps. Less than 10 SCF 
would be needed  by using CUTOFF 2300, as was empirically found. 
I will be happy to provide complete input files, if needed.

Thank you,
Slava


On Monday, April 13, 2020 at 2:11:55 PM UTC-4, tkuehne wrote:
>
> Dear Vyacheslav, 
>
> such a large density cutoff strikes me as odd. SCF convergence behavior 
> isn’t 
> a good indicator to converge CUTOFF and REL_CUTOFF. Please have a look 
> at: https://www.cp2k.org/howto:converging_cutoff 
> IMHO, Total charge density on r- and g-space grids are 
> much stronger indicators …
>
> Cheers, 
> Thomas
>
> Am 13.04.2020 um 19:55 schrieb Vyacheslav Bryantsev <
> vyac... at gmail.com <javascript:>>:
>
> 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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>
>
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