[CP2K-user] [CP2K:13118] SCAN XC density functional: Do we have to use specific PSEUDOPOTENTIALS for SCAN? Are they available?
Thomas Kühne
tku... at gmail.com
Mon Apr 13 18:11:46 UTC 2020
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 <vyachesla... at gmail.com>:
>
> 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 <http://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 <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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