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

[Vyacheslav Bryantsev]

Dear All,

Thank you for your helpful comments.
Indeed, Mg2+ is patological, because when I consider ZnCl2 melt, I have no 
problem with SCF convergence at much lower grid values. 
I could still get results by using a lot of CPUs. I have no experience with 
GAPW. Is it going to be much slower than GPW?

Thank you,
Slava

On Tuesday, April 14, 2020 at 5:41:12 PM UTC-4, Matt W wrote:
>
> There could be two factors to the reported huge cutoff for the MgCl2 salt:
>
> (i) Mg is nearly pathological, you need a huge cutoff with unsmoothed GPW 
> scheme to get the 2s semi-core states reasonalbly (so GAPW is much better)
> (ii) SCAN is known to be 'difficult' in some sense, needed much tighter 
> settings (meta GGA). I am not sure if it is compatible with GAPW method?
>
> For other sytems the cutoff should be less extreme.
>
> Matt
>
> On Tuesday, April 14, 2020 at 8:18:46 AM UTC+1, Marcella Iannuzzi wrote:
>>
>> Dear Slava,
>>
>> Have you tried GAPW. A much lower cutoff should be sufficient and it 
>> possibly improves the convergence.
>> Kind regards, 
>> Marcella
>>
>>
>> On Monday, April 13, 2020 at 7:55:08 PM UTC+2, Vyacheslav Bryantsev wrote:
>>>
>>> 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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