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

[Hua Tian]

Dear Bryantsev and CP2K developers,
  In fact, I have the same question. The other day I did some tests, and 
found that the misconvergence of SCF could be probably attributed to the 
default PW method in *XC_DERIV*.
  According to the Reference Manual, the default parameters for the 
*&XC_GRID* section are:
*&XC_GRID*
*  XC_DERIV PW*
*  XC_SMOOTH_RHO NONE*
*&END XC_GRID*
In my FPMD simulations for aqueous solutions by using SCAN functional, with 
these settings, SCF did not converge even with *CUTOFF 600*.
  However, when I followed the guidance in www.cp2k.org/gpw, and set *XC_DERIV 
SPLINE3*, i.e., 
*&XC_GRID*
*  XC_DERIV SPLINE3*
*  XC_SMOOTH_RHO NONE*
*&END XC_GRID*
the SCF converged.
  Besides, the *NN10_SMOOTH* / *NN10* settings I mentioned before were also 
applicable for *CUTOFF 600*.
  I am also hoping for the explanation from CP2K developers.
Sincerely,
Tian Hua


在 2020年7月27日星期一 UTC+8上午9:56:57，Vyacheslav Bryantsev写道：
>
> Dear Tian and CP2K developers,
>
> I confirm for my system, which is a concentrated  aqueous salt, these 
> options work with  CUTOFF=800 and it would probably work at smaller values 
> also.
>
>         &XC_GRID
>
>                XC_DERIV NN10_SMOOTH
>
>                XC_SMOOTH_RHO NN10
>         &END XC_GRID
> Interestingly, removing them requires CUTOFF of at least 1200.
> A question to developers: What do these parameters do and what do those 
> specific options mean?
> There is very little information in the manual about these options.
>
> Thank you
> Slava
> Vyacheslav Bryantsev
>
> On Thursday, June 4, 2020 at 6:22:38 AM UTC-4, Hua Tian wrote:
>>
>> Dear Prof. Hutter and Bryantsev,
>> In my FPMD simulations for aqueous solutions by using SCAN functional 
>> (with the MOLOPT-SR basis sets and the GTH  pseudopotentials for SCAN from 
>> the website in your e-mail.), I found that smoothing methods (e.g., 
>> &XC_GRID / XC_DERIV NN10_SMOOTH / XC_SMOOTH_RHO NN10 / &END XC_GRID) was 
>> probably important for the convergence of SCF. For a simulation using SCAN 
>> functional with CUTOFF 400 that SCF did not converge, adding the &XC_GRID 
>> part methoned above made the SCF converge. However, I did not know if this 
>> setting would influence the accuracy of simulations.
>> Sincerely, 
>> Tian Hua
>>
>>
>> 在 2020年4月10日星期五 UTC+8下午6:31:42，jgh写道：
>>>
>>> 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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