How to perform hybrid functional calculations for large systems using the pob-TZVP-rev2 basis set?

[yis...@163.com]

To the CP2K Development Team,

Hello,

I am a beginner in DFT calculations and am currently learning to use CP2K for calculations with the PBE0 hybrid functional. My research involves a Mo-doped NiFe-LDH system. I have constructed a 6×8×3 supercell containing a total of 720 atoms. Given the significant presence of Ni, Fe, and O in the system, when using the GTH pseudopotential with the DZVP-MOLOPT-SR basis set, convergence was only achieved with very high values of CUTOFF and REL_CUTOFF. Therefore, I intend to use the GAPW method to reduce computational cost and improve accuracy.

Currently, I am employing the pob-TZVP-rev2 basis set for all-electron calculations, along with pob-DZVP-rev2 as the ADMM basis set to accelerate the hybrid functional calculation. During the calculation, I first performed a pure functional calculation using the pob-TZVP-rev2 basis set. Then, I used the wavefunction generated from this calculation as the initial guess for the hybrid functional calculation. Unfortunately, the hybrid functional calculation does not seem to proceed—after running continuously for 4 hours, the calculation remains stuck at the interface shown in the attached image and does not appear to enter the self-consistent iteration process.

The supercomputer I am using is equipped with Intel Xeon Platinum Processors (3rd Gen, 64 cores) and 256 GB of memory. I would like to ask the developers for their insight into the following:

1. What might be causing this issue?

2. How should hybrid functional calculations be conducted for such a system?

3. Could you recommend a more suitable basis set for this system?

For your reference, I have attached the input and output files from my CP2K calculation at the end of this email.

Thank you for your attention and assistance.

Best regards,

yisichi

[Augustin Bussy]

Hi Yisichi,

Your calculation is most likely not stuck, but proceeding. Hybrid DFT in the condensed phase can be very expensive, even when using ADMM and non-diffuse basis sets like pob-DZVP-rev2. Given an optimized input file, the only solution is to used more resources.

That being said, your input in not perfect. In particular, you are using and extremely tight value for EPS_PGF_ORB. The default value if 1E-5, and particularly accurate calculations can used 1E-6. I recommend you to change it. The MIN_PAIR_LIST_RADIUS option that you commented out is a much more efficient solution to the "Kohn Sham matrix occupancy warning": use this instead. For performance, make sure to also optimize the MAX_MEMORY keyword to the specifications of your computer. See the "Hartree−Fock and Hybrid Density Functional Theory" section of our latest paper (https://pubs.acs.org/doi/full/10.1021/acs.jpcb.5c05851) to understand the meaning of these keywords.

Best,

Augustin

[Jürg Hutter]

Hi
one more point:
For the atom types with all-electron basis sets, I would suggest to use ADMM basis sets
from BASIS_ADMM_ae. The admm-1 or maybe admm-2 are recommended for your case.

regards
JH

________________________________________
From: cp...@googlegroups.com <cp...@googlegroups.com> on behalf of Augustin Bussy <augusti...@gmail.com>
Sent: Thursday, January 22, 2026 10:23 AM
To: cp2k
Subject: [CP2K:22054] Re: How to perform hybrid functional calculations for large systems using the pob-TZVP-rev2 basis set?

Hi Yisichi,
Your calculation is most likely not stuck, but proceeding. Hybrid DFT in the condensed phase can be very expensive, even when using ADMM and non-diffuse basis sets like pob-DZVP-rev2. Given an optimized input file, the only solution is to used more resources.

That being said, your input in not perfect. In particular, you are using and extremely tight value for EPS_PGF_ORB. The default value if 1E-5, and particularly accurate calculations can used 1E-6. I recommend you to change it. The MIN_PAIR_LIST_RADIUS option that you commented out is a much more efficient solution to the "Kohn Sham matrix occupancy warning": use this instead. For performance, make sure to also optimize the MAX_MEMORY keyword to the specifications of your computer. See the "Hartree−Fock and Hybrid Density Functional Theory" section of our latest paper (https://pubs.acs.org/doi/full/10.1021/acs.jpcb.5c05851) to understand the meaning of these keywords.

Best,
Augustin

On Wednesday, 21 January 2026 at 17:41:23 UTC+1 yis...@163.com wrote:

To the CP2K Development Team,

Hello,

I am a beginner in DFT calculations and am currently learning to use CP2K for calculations with the PBE0 hybrid functional. My research involves a Mo-doped NiFe-LDH system. I have constructed a 6×8×3 supercell containing a total of 720 atoms. Given the significant presence of Ni, Fe, and O in the system, when using the GTH pseudopotential with the DZVP-MOLOPT-SR basis set, convergence was only achieved with very high values of CUTOFF and REL_CUTOFF. Therefore, I intend to use the GAPW method to reduce computational cost and improve accuracy.

Currently, I am employing the pob-TZVP-rev2 basis set for all-electron calculations, along with pob-DZVP-rev2 as the ADMM basis set to accelerate the hybrid functional calculation. During the calculation, I first performed a pure functional calculation using the pob-TZVP-rev2 basis set. Then, I used the wavefunction generated from this calculation as the initial guess for the hybrid functional calculation. Unfortunately, the hybrid functional calculation does not seem to proceed—after running continuously for 4 hours, the calculation remains stuck at the interface shown in the attached image and does not appear to enter the self-consistent iteration process.

The supercomputer I am using is equipped with Intel Xeon Platinum Processors (3rd Gen, 64 cores) and 256 GB of memory. I would like to ask the developers for their insight into the following:

1. What might be causing this issue?

2. How should hybrid functional calculations be conducted for such a system?

3. Could you recommend a more suitable basis set for this system?

For your reference, I have attached the input and output files from my CP2K calculation at the end of this email.

Thank you for your attention and assistance.

Best regards,

yisichi

[微信图片_20260122004005_251_55.png]

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[yis...@163.com]

Thank you for your suggestion. After increasing EPS_PGF_ORB to 1E-6, the calculation proceeded smoothly.

[yis...@163.com]

Thank you for your suggestion. After replacing the ADMM basis set for hydrogen and oxygen elements with admm-1, the calculation ran very smoothly.