[CP2K-user] [CP2K:22200] Re: Converge EPS_SCHWARZ and CUTOFF_RADIUS for hybrid functionals

[Frederick Stein]

Dear Max,
Both parameters are determined differently.
CUTOFF_RADIUS needs to be less than half of the distance of an atom to its 
nearest image. For sufficiently large cells, you may even reduce it to 
values at the order of 5-7 A (please check convergence of your results in 
that case). If this parameter is not yet converged, you employ the 
MULTIPLE_UNIT_CELL as you suggested. Convergence is expected if 
CUTOFF_RADIUS can be set to values of at least 5 A.
EPS_SCHWARZ is determined by checking convergence of total energies. A good 
starting point is 1E-6 but larger values may be necessary, especially if 
you set "SCREEN_ON_INITIAL_P T" or with ADMM (ADMM is recommended).
Best,
Frederick

Max H schrieb am Freitag, 24. April 2026 um 17:05:35 UTC+2:

> Dear all,
>
> I plan on doing some single point calculations with the PBE0 functional 
> and a ccGRB basis and would appreciate advice on the selection of 
> appropriate parameters, because I have not found information of sufficient 
> detail.
>
> I read in the recent review (JPhysChemB, "The CP2K Program Package Made 
> Simple") and in various other sources that the EPS_SCHWARZ and 
> CUTOFF_RADIUS parameters are crucial for accuracy and computational 
> efficiency.
>
> What is the typical approach to converge these values? Are single-point 
> calculations with one SCF cycle sufficient as soon as energy convergence is 
> observed (comparable to the convergence protocols for CUTOFF and 
> REL_CUTOFF)?
>
> When studying metallic systems, which values of CUTOFF_RADIUS can be 
> expected?
> Supposing that the CUTOFF_RADIUS did not converge at half the smallest 
> cell dimension, is the best approach then to set MULTIPLE_UNIT_CELL 2 2 1 
> (xy periodic system) in the &CELL block or do special restrictions arise?
>
> I appreciate your kind advice.
>
> Best,
> Max
>
>
>
>

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