[CP2K-user] [CP2K:17620] Re: Large discrepancy in xTB results from CP2K vs DFTB+

Magnus Rahm magnus at compulartech.com
Tue Sep 6 20:29:17 UTC 2022
Previous message (by thread): [CP2K-user] [CP2K:17617] Re: Large discrepancy in xTB results from CP2K vs DFTB+
Next message (by thread): [CP2K-user] [CP2K:17620] Re: Large discrepancy in xTB results from CP2K vs DFTB+
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Hi,

Thanks for the prompt fix! It made a significant difference but doesn't 
seem to resolve the discrepancy with DFTB+ (please see attached figure). 
Mulliken charges changed "in the right direction" but still differ very 
significantly compared to DFTB+.

Kind regards,
Magnus Rahm



On Tuesday, September 6, 2022 at 5:36:30 PM UTC+2 jgh wrote:

> Hi
>
> the updates are now on Github (Trunk version).
> This should at least fix the strange behavior for changes of EPS_DEFAULT.
>
> regards
>
> JH
>
> ________________________________________
> From: cp... at googlegroups.com <cp... at googlegroups.com> on behalf of Jürg 
> Hutter <hut... at chem.uzh.ch>
> Sent: Tuesday, September 6, 2022 11:37 AM
> To: cp... at googlegroups.com
> Subject: Re: [CP2K:17614] Re: Large discrepancy in xTB results from CP2K 
> vs DFTB+
>
> Hi
>
> I think I found the problem. This is in fact a bug in CP2K and is related 
> to the damping of
> the "short range" part of the Coulomb term. As mentioned before this short 
> range part
> is not short range at all, even diverging in periodic systems. We use a 
> damping function
> for this term and the radius is taken from the range of the basis function 
> on each atom.
> The bug is now, that this range is not a constant but depends on 
> EPS_DEFAULT.
> I will work on a solution, but at least the default settings will cause 
> considerable changes
> in the energies of periodic systems.
>
> regards
>
> JH
>
> ________________________________________
> From: cp... at googlegroups.com <cp... at googlegroups.com> on behalf of Magnus 
> Rahm <mag... at compulartech.com>
> Sent: Monday, September 5, 2022 3:19 PM
> To: cp2k
> Subject: Re: [CP2K:17609] Re: Large discrepancy in xTB results from CP2K 
> vs DFTB+
>
> Hi,
>
> Thank you for valuable input! Here's a breakdown of energies for a 
> periodic LiO2 system (where CP2K and DFTB+ disagree).
> CP2K:
>
> Core Hamiltonian energy: -609.45757320827579
> Repulsive potential energy: 2.86335541921533
> Electronic energy: -65.73940900376786
> DFTB3 3rd order energy: 9.00274299587460
> Dispersion energy: -2.00065978643714
> Correction for halogen bonding: 0.00000000000000
>
> Total energy: -665.33154358339084
>
> outer SCF iter = 1 RMS gradient = 0.49E-06 energy = -665.3315435834 
> <(331)%20543-5834>
> outer SCF loop converged in 1 iterations or 10 steps
>
> And the same system with DFTB+ (I don't know this is the best breakdown I 
> can get from DFTB+? This info is from detailed.out.):
>
> Fermi level: -0.1574062769 H -4.2832 eV
> Band energy: -254.9890864567 H -6938.6061 eV
> TS: 0.0000000000 H 0.0000 eV
> Band free energy (E-TS): -254.9890864567 H -6938.6061 eV
> Extrapolated E(0K): -254.9890864567 H -6938.6061 eV
> Input / Output electrons (q): 864.0000000000 864.0000000000
>
> Energy H0: -610.3586854777 H -16608.7049 eV
> Energy SCC: 13.1915555608 H 358.9605 eV
> Total Electronic energy: -597.1671299169 H -16249.7444 eV
> Repulsive energy: 0.0000000000 H 0.0000 eV
> Total energy: -597.1671299169 H -16249.7444 eV
> Extrapolated to 0: -597.1671299169 H -16249.7444 eV
> Total Mermin free energy: -597.1671299169 H -16249.7444 eV
> Force related energy: -597.1671299169 H -16249.7444 eV
>
>
> ----------------------------------------------------------------------------------------------------------------
> For reference, here are the equivalent breakdowns for the LiF molecule, 
> where the total energies do match quite well.
> CP2K:
>
> Core Hamiltonian energy: -5.57594122418510
> Repulsive potential energy: 0.00036401843654
> Electronic energy: 0.08477836575096
> DFTB3 3rd order energy: -0.00385103760005
> Dispersion energy: -0.00008325087778
> Correction for halogen bonding: 0.00000000000000
>
> Total energy: -5.49473312847544
>
> outer SCF iter = 1 RMS gradient = 0.12E-06 energy = -5.4947331285
> outer SCF loop converged in 1 iterations or 25 steps
>
> DFTB+
> Fermi level: -0.3434874008 <(343)%20487-4008> H -9.3468 eV
> Band energy: -3.7493389034 H -102.0247 eV
> TS: 0.0000000000 H 0.0000 eV
> Band free energy (E-TS): -3.7493389034 H -102.0247 eV
> Extrapolated E(0K): -3.7493389034 H -102.0247 eV
> Input / Output electrons (q): 8.0000000444 8.0000000000
>
> Energy H0: -5.5743451431 <(574)%20345-1431> H -151.6856 eV
> Energy SCC: 0.0807122067 H 2.1963 eV
> Total Electronic energy: -5.4936329365 H -149.4894 eV
> Repulsive energy: 0.0000000000 H 0.0000 eV
> Total energy: -5.4936329365 H -149.4894 eV
> Extrapolated to 0: -5.4936329365 H -149.4894 eV
> Total Mermin free energy: -5.4936329365 H -149.4894 eV
> Force related energy: -5.4936329365 H -149.4894 eV
>
>
> ----------------------------------------------------------------------------------------------------------------
>
> > I recently run variable-cell optimization of various molecular crystals 
> and I found xTB at CP2K ultra sensitive to EPS_DEFAULT. Tested from 1e-5 to 
> 1e-24 (with EPS_SCF 1e-8), and no convergence happened.
>
> Thank you for sharing this info! I tried a series of calculations with 
> LiO2 using varying values of EPS_DEFAULT (using default EPS_SCF) and found 
> the same effect; no convergence with EPS_DEFAULT (or perhaps unreasonably 
> slow convergence). I attach a figure showing these results, including the 
> energy broken down into the different parts as specified in the CP2K 
> output. Note the energy scale, the changes with EPS_DEFAULT are really 
> quite substantial. In the LiF (non-PBC) case, the corresponding curves look 
> completely flat on the same scale. I don't know what to make of this 
> result, but perhaps someone else does?
>
> Magnus
>
> [X]
> On Monday, September 5, 2022 at 12:18:26 PM UTC+2 jazz... at gmail.com wrote:
> I recently run variable-cell optimization of various molecular crystals 
> and I found xTB at CP2K ultra sensitive to EPS_DEFAULT. Tested from 1e-5 to 
> 1e-24 (with EPS_SCF 1e-8), and no convergence happened. I just ended up 
> with EPS_DEFAULT 1e-10 as a "gut" choice. Also, the behavior of xTB at CP2K is 
> doutfull with MD even at ambiant conditions, where the converged volume is 
> barely larget than at 0K. Depending on EPS_DEFAULT, it can even be smaller 
> at ambient T. Weird. The behavior of DFTB2 at CP2K is far better.
>
> I found that DFTB+ has other issues. xTB at DFTB+ has no convergence issue, 
> but the recommended variable-cell optimization algorithm has flaws. The 
> unit cell and a supercell does NOT always end up with related lattice 
> parameters. The main issue is that some 90° angles are not preserved with 
> DFTB+ whereas CP2K does (with no symmetry enforced, obviously). Some 
> inconsistencies appears in DFTB+ with a lattice dimensions < 10 angstroms 
> in the unit cell versus > 10 angstroms in the supercell. A proper tight 
> mesh of k-points does not improve. So I'm afraid that xTB at DFTB+ (or DFTB+, 
> actually) cannot be a relevant choice for crystal structure predictions, 
> for instance.
>
> xTB may be unreliable with CP2K and DFTB+, but for the different reasons 
> above. You can check these weird behaviors with your own crystals of 
> interest.
>
> Xavier
>
>
>
> Le lun. 5 sept. 2022, 3:59 AM, Jürg Hutter <hut... at chem.uzh.ch> a écrit :
> Hi
>
> thank you for testing. Could you send a break down of the energies for the 
> LiF molecule for
> the two codes? That might help to recognize the source of the difference.
>
> regards
>
> JH
>
> ________________________________________
> From: cp... at googlegroups.com <cp... at googlegroups.com> on behalf of Magnus 
> Rahm <mag... at compulartech.com>
> Sent: Monday, September 5, 2022 8:40 AM
> To: cp2k
> Subject: [CP2K:17599] Re: Large discrepancy in xTB results from CP2K vs 
> DFTB+
>
> For the record, the problem is the same in CP2K version 2022.1.
>
> On Thursday, September 1, 2022 at 12:48:35 PM UTC+2 Magnus Rahm wrote:
> Dear all,
>
> I want to use CP2K (version 8.2, trying to get a more recent version 
> compiled) together with xTB for a crystal containing Li and O. I get 
> strange results already for a simple LiO2 crystal:
>
> * There is a very large discrepancy compared to DFTB+ (version 22.1).
> * Mulliken charges tend to be large, meaning that CHECK_ATOMIC_CHARGES 
> stops the SCF. If I turn it off, the system tends to converge 
> systematically to values just outside the "chemical range". Mulliken 
> charges obtained by DFTB+ are significantly smaller (and within "chemical 
> range").
> * The energy-volume curve looks strange and very different from DFTB+.
>
> I have tried converging with respect to system size and the EWALD / ALPHA 
> and GMAX parameters, but they have only a marginal impact. I have tried 
> similar calculations for a number of periodic systems. Sometimes I get 
> agreement, sometimes not. I also tried calculations for CO and NO molecules 
> which agree perfectly between CP2K and DFTB+, whereas an artificial LiF 
> molecule does not.
>
> A perhaps related issue was reported in 
> https://groups.google.com/g/cp2k/c/oFwgGcQuySs but the solutions 
> suggested there did not solve my problem.
>
> I attach input scripts for CP2K and DFTB+, as well as a figure showing the 
> E-V curve for LiO2 obtained with CP2K and DFTB+. I'm new to CP2K, DFTB+ and 
> xTB so I suspect I have made some simple mistake, and any advice is 
> appreciated.
>
> Kind regards,
> Magnus Rahm
>
>
>
>
>
>
> --
> 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 on the web visit 
> https://groups.google.com/d/msgid/cp2k/c51e70a2-7f7a-4887-8ada-971d840a1b13n%40googlegroups.com
> <
> https://groups.google.com/d/msgid/cp2k/c51e70a2-7f7a-4887-8ada-971d840a1b13n%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.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/cp2k/ZR0P278MB075983A13AA78F53FFB422559F7F9%40ZR0P278MB0759.CHEP278.PROD.OUTLOOK.COM
> .
>
> --
> 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 on the web visit 
> https://groups.google.com/d/msgid/cp2k/7d455fce-a22e-44f1-ac48-18495f9553a5n%40googlegroups.com
> <
> https://groups.google.com/d/msgid/cp2k/7d455fce-a22e-44f1-ac48-18495f9553a5n%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.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/cp2k/ZR0P278MB0759EEC38142F9D207742F549F7E9%40ZR0P278MB0759.CHEP278.PROD.OUTLOOK.COM
> .
>

-- 
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 on the web visit https://groups.google.com/d/msgid/cp2k/3542e78b-ca60-4753-bb72-b077a2517dbbn%40googlegroups.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20220906/7112efd7/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: EV-LiO2.pdf
Type: application/pdf
Size: 17202 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20220906/7112efd7/attachment-0001.pdf>
Previous message (by thread): [CP2K-user] [CP2K:17617] Re: Large discrepancy in xTB results from CP2K vs DFTB+
Next message (by thread): [CP2K-user] [CP2K:17620] Re: Large discrepancy in xTB results from CP2K vs DFTB+
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
More information about the CP2K-user mailing list