[CP2K-user] [CP2K:17210] Best practices for large non periodic molecules

[Marco Severi]

Thank you very much, I will try as soon as possible.

Best,
Marco

Il giorno mercoledì 22 giugno 2022 alle 16:45:14 UTC+2 hehn... at gmail.com ha 
scritto:

> Dear Marco, 
>
> regarding convergence I would recommend to use the OUTER_SCF keyword and 
> SCF_GUESS RESTART, giving a relatively small number of inner SCF cycles, 
> maybe 20 to 50. Also choosing DIIS as minimizer can help to speed up 
> convergence.
>
> Best regards,
>
> Anna
>
> Am Mi., 22. Juni 2022 um 14:11 Uhr schrieb Marco Severi <
> marcos... at gmail.com>:
>
>> Good morning, 
>>
>> I am a fairly new CP2K user and I am trying to perform some calculations 
>> on a non-periodic molecular system of 657 atoms.  
>>
>> I am writing because I do not fully understand which keywords I should 
>> use and I have the feeling I am doing some rookie mistakes.
>>
>> At the moment I am trying to do some DFT calculations with the PBE 
>> functional and the dispersion correction. The molecule is about 35 Angstrom 
>> long and so I chose a 50x50x50 cell. The system is organometallic, contains 
>> 8 Fe atoms and the BF4- counterions. I tried to use the DZVP basis set but 
>> I quickly reached 100GB of occupied memory, is it normal? I am using the 
>> non "PERIODIC NONE" and "PSOLVER WAVELET" keywords  and the FULL_KINETIC 
>> preconditioner. I am using 5 grids with cutoff equal to 400 and rel_cutoff 
>> equal to 60. I tried to maintain all the other options as “default” as 
>> possible. I enclose the input and the output of the calculation. (I am 
>> aware that the attached example did not converge and that I can change the 
>> number of SCF iterations)
>>
>> I would like to know if those options are adequate for the type of 
>> calculation I am performing and if there is room for any improvement in the 
>> efficiency or in the convergence, since this calculation seems to converge 
>> particularly slowly. Any help or reference will be greatly appreciated. 
>>
>> Thanks in advance for your time and patience. 
>>
>> Kind regards, 
>>
>> Marco Severi 
>>
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>>
>

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