[CP2K-user] [CP2K:20516] Re: revPBE0 CELL_OPT not converging

[jgh]

Hi
please use STRESS_TENSOR ANALYTICAL
In your CASTEP run you have 3x3x2 k-points. Use the same in CP2K (special 
care needed for hybrid functionals)
or use a corresponding supercell.

regards
JH

On Monday, July 29, 2024 at 12:55:16 PM UTC+2 albesan... at gmail.com wrote:

> Hi Frederick,
>
> Thanks a lot for all your suggestions.
>
> Best,
>
> Alberto 
>
> Il giorno lunedì 29 luglio 2024 alle 11:08:01 UTC+2 Frederick Stein ha 
> scritto:
>
>> Dear Alberto,
>> - Did you check the convergence of EPS_SCHWARZ and EPS_SCHWARZ_FORCES 
>> (not set by you, check the manual)? With ADMM, it needs to be chosen 
>> tighter than without ADMM. You should also check the convergence of nuclear 
>> forces and the stress tensor.
>> - Why do you calculate the stress tensor numerically? This is usually not 
>> too accurate.
>> - The cell might be too small. Beware that HF energies with cutoff radii 
>> far below 5 A are usually not well converged. Compare this with your setup 
>> in CASTEP (if I understand it correctly).
>> You may also pre-optimize cell size and geometry independently of each 
>> other before optimizing them simultaneously.
>> Best,
>> Frederick
>>
>> alberto santonocito schrieb am Montag, 29. Juli 2024 um 10:48:18 UTC+2:
>>
>>> Dear CP2K Users,
>>>
>>> I attempted a CELL_OPT calculation using the revPBE0 functional, but 
>>> unfortunately, the calculation is not converging, and after a few steps, 
>>> the structure deviates significantly from the experimental one.
>>> I chose to use revPBE0 with CP2K because, in CASTEP, I found a good 
>>> agreement between the experimental and calculated structures using the 
>>> revPBE functional. However, my computational resources are insufficient to 
>>> test revPBE0 in CASTEP.
>>> With CP2K, this is possible due to the Auxiliary Density Matrix Methods 
>>> that reduce computational costs. Unfortunately, the calculation with CP2K 
>>> does not converge.
>>> I would appreciate any suggestions regarding this issue.
>>> I have attached the CP2K input and output  files, along with the CASTEP 
>>> input and output.
>>>
>>> Thanks in advance for your help!
>>>
>>

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