[CP2K-user] [CP2K:22082] DFTB3 D3(BJ) GAMMA

[Dobromir A Kalchevski]

Thank you again,  Jürg.

Best Regards,
Dobromir

  

On Tuesday, February 3, 2026 at 10:35:41 AM UTC+2 Jürg Hutter wrote:

> Hi
>
> I would strongly suggest to check that CP2K can correctly read your SK 
> files.
> When DFTB was included in CP2K, only the files distributed with CP2K were
> available. Since then the DFTB community has added new functionality and
> parameters that are missing in CP2K.
>
> regards
> JH
>
> ________________________________________
> From: cp... at googlegroups.com <cp... at googlegroups.com> on behalf of 
> Dobromir A Kalchevski <dobro... at gmail.com>
> Sent: Tuesday, February 3, 2026 1:12 AM
> To: cp2k
> Subject: Re: [CP2K:22078] DFTB3 D3(BJ) GAMMA
>
> Hello,
>
> many thanx for the answers.
>
> Yes, I found the DFTB3 examples in the test files and I tried those 
> inputs, but to no avail. I played around with some of the settings and I 
> think I found something that works, but I'm no sure it gives the right 
> barrier.
>
> With the settings below (the rest of the input is the same, as the 
> uploaded in the first post) I get broken calculations - either the reagent 
> breaks or different H atoms (one from the MM region, one from the QM) get 
> way too close and the calculation stops:
>
> DFTB3 + D3(BJ) with default D3BJ_SCALING from the test files, no 
> HB_SR_GAMMA (as per the test files) and no EWALD (as per the test files) - 
> eventually the reagent (QM region) breaks in pieces:
> &DFTB
> DIAGONAL_DFTB3 T
> !ORTHOGONAL_BASIS F
> SELF_CONSISTENT T
> DO_EWALD F
> DISPERSION T
> !HB_SR_GAMMA T
> &PARAMETER
> PARAM_FILE_PATH ${LIBPATH}/DFTB/3ob-3-1
> PARAM_FILE_NAME param_file
> DISPERSION_TYPE D3(BJ)
> DISPERSION_PARAMETER_FILE ${LIBPATH}/dftd3.dat
> D3BJ_SCALING 1.0 0.4 1.5 4.0
> !HB_SR_PARAM 4.0
> &END PARAMETER
> &END DFTB
> ----
>
> DFTB3 + D3(BJ) with default D3BJ_SCALING from the test files + HB_SR_GAMMA 
> (= 4.2, as per the original paper) and no EWALD (as per the test files) - H 
> atoms get way too close (< 1 A) and the calculations stops:
> &DFTB
> DIAGONAL_DFTB3 T
> !ORTHOGONAL_BASIS F
> SELF_CONSISTENT T
> DO_EWALD T
> DISPERSION T
> HB_SR_GAMMA T
> &PARAMETER
> PARAM_FILE_PATH ${LIBPATH}/DFTB/3ob-3-1
> PARAM_FILE_NAME param_file
> DISPERSION_TYPE D3(BJ)
> DISPERSION_PARAMETER_FILE ${LIBPATH}/dftd3.dat
> D3BJ_SCALING 1.0 0.4 1.5 4.0
> HB_SR_PARAM 4.2
> &END PARAMETER
> &END DFTB
> ----
>
> DFTB3 + D3(BJ) with original D3BJ_SCALING from the original paper + 
> HB_SR_GAMMA (= 4.2, as per the original paper), no EWALD (as per the test 
> files) - H atoms get way too close (< 1 A) and the calculations stops:
> &DFTB
> DIAGONAL_DFTB3 T
> !ORTHOGONAL_BASIS F
> SELF_CONSISTENT T
> DO_EWALD F
> DISPERSION T
> HB_SR_GAMMA T
> &PARAMETER
> PARAM_FILE_PATH ${LIBPATH}/DFTB/3ob-3-1
> PARAM_FILE_NAME param_file
> DISPERSION_TYPE D3(BJ)
> DISPERSION_PARAMETER_FILE ${LIBPATH}/dftd3.dat
> D3BJ_SCALING 1.0 .5719 .5883 3.6017
> HB_SR_PARAM 4.2
> &END PARAMETER
> &END DFTB
> ---
>
> ORTHOGONAL_BASIS T always breaks the calculation from the beginning (not a 
> single geometry in the output), so I guess 3ob-3-1 does not have an 
> orthogonal basis or DFTB3 simply does not use one. As I can see - the 
> default in CP2K is FALSE, anyway.
> DO_EWALD F breaks even DFTB2 calculations - the reagent (QM region) breaks 
> in pieces
> ---
>
> However, the following setup seems to work, although I'm not sure I can 
> trust the barrier (it is very sensitive to intermolecular interactions and 
> it seems kind of high, and there is no available experimental value):
>
> DFTB3 + D3(BJ), no D3BJ_SCALING keyword (I let cp2k determine s6, sr6, s8 
> automatically, as suggested in a recent new thread in this google group) + 
> HB_SR_GAMMA (=4 as usual default), with EWALD - it seems to work:
> &DFTB
> DIAGONAL_DFTB3 T
> SELF_CONSISTENT T
> DO_EWALD T
> DISPERSION T
> HB_SR_GAMMA T
> &PARAMETER
> PARAM_FILE_PATH ${LIBPATH}/DFTB/3ob-3-1
> PARAM_FILE_NAME param_file
> ! UFF_FORCE_FIELD uff_table
> DISPERSION_TYPE D3(BJ)
> DISPERSION_PARAMETER_FILE ${LIBPATH}/dftd3.dat
> HB_SR_PARAM 4
> &END PARAMETER
> &END DFTB
> ---
>
> Next I will try to explicitly provide the Hubbard parameters with in the 
> input with DFTB3_PARAM.
>
> Thank you again for the help.
> If you can think of anything else - please - tell me.
>
> Best Regards,
> Dobromir
>
>
> On Monday, February 2, 2026 at 11:23:58 AM UTC+2 Jürg Hutter wrote:
> Hi
>
> 1) and 2) Have a look in "tests/DFTB/regtest-vdw" . There you find some 
> examples on how to use D3 with DFTB.
> 3) The D3(BJ) parameters have to be given in the input file. The data file 
> only contains the atom specific parameters,
> not the method parameters.
> 4) Yes, this is the DFTB3 parameter. I don't know if CP2K can read the 
> parameter from the DFTB parameter file. I would have to check.
> 5) You need the keyword. According to the manual the default is not to use 
> it.
> 6) I cannot answer this question.
>
> regards
> JH
>
> ________________________________________
> From: cp... at googlegroups.com <cp... at googlegroups.com> on behalf of 
> Dobromir A Kalchevski <dobro... at gmail.com>
> Sent: Saturday, January 31, 2026 11:21 AM
> To: cp2k
> Subject: [CP2K:22073] DFTB3 D3(BJ) GAMMA
>
> Hello valued developers and users,
>
> I am trying to setup DFTB3 with D3 correction and GAMMA damping and I 
> can't find the answers to all of my questions in the forum threads. Also 
> some answers are not completely clear to me.
>
> 1) If I am to use the D3 correction - is it enough to include
> DISPERSION_TYPE D3(BJ)
> DISPERSION_PARAMETER_FILE ${LIBPATH}/dftd3.dat
>
> or should I also include the &VDW_POTENTIAL section and where if I am not 
> using DFT (&XC section)
>
> 2) does D3(BJ) work with DFTB3 or does only D3 work
>
> 3) are both the D3 and the D3(BJ) parameters in the dft3d.dat file. If not 
> - for D3(BJ) I can find only a1, a2 and s8, but I can't find anywhere the 
> fourth one. Why are the default values set to 0
>
> 4) is the keyword DFTB3_PARAM in KIND the Hubbard parameter and is it 
> necessary. The 3ob .skf files technically include it, basically does CP2K 
> read it from the .skfs.
>
> 5) is using 3ob enough for DFTB3 or do I have to include the keyword 
> DIAGONAL_DFTB3 in &DFTB
>
> 6) if HB_SR_GAMMA is the GAMMA damping for hydrogen bonds, is its use 
> recommended for general organics at the moment or it would rather worsen 
> the results, as before
>
> I am attaching an example input file for QM/MM Metadynamics.
>
> Best Regards,
> Dobromir
>
>
>
> --
> You received this message because you are subscribed to the Google Groups 
> "cp2k" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to cp2k+uns... at googlegroups.com<mailto:cp2k+uns... at googlegroups.com
> >.
> To view this discussion visit 
> https://groups.google.com/d/msgid/cp2k/e18f9019-605d-408b-a268-100e577c52f8n%40googlegroups.com
> <
> https://groups.google.com/d/msgid/cp2k/e18f9019-605d-408b-a268-100e577c52f8n%40googlegroups.com?utm_medium=email&utm_source=footer
> >.
>
> --
> You received this message because you are subscribed to the Google Groups 
> "cp2k" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to cp2k+uns... at googlegroups.com<mailto:cp2k+uns... at googlegroups.com
> >.
> To view this discussion visit 
> https://groups.google.com/d/msgid/cp2k/17f23652-327a-4472-a00e-62ffbce76edfn%40googlegroups.com
> <
> https://groups.google.com/d/msgid/cp2k/17f23652-327a-4472-a00e-62ffbce76edfn%40googlegroups.com?utm_medium=email&utm_source=footer
> >.
>

-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/cp2k/c3ec3e3b-f34f-459e-9f1f-1a14fdd4c1b6n%40googlegroups.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20260203/91a19e8e/attachment.htm>