[CP2K-user] [CP2K:21483] Re: frequencies

[Sihem AZIZI]

Dear frederick,
Thanks a lot for your response.
I have another question for you. On another machine I ran an optimization 
calculation for a Ru slab (3 layers) with an H2 molecule. And the 
calculation has been running for a month. What should I do to make it 
converge faster?
Thank you again for your help.
Sihem

On Monday, May 19, 2025 at 9:05:04 PM UTC+1 Frederick Stein wrote:

> Dear Sihem,
> How much time do you need for a force calculation on the same machine with 
> 8 processes? Your total runtime will be 6*<number of atoms> in your system 
> as the elements of the Hessian will be determined from symmetric finite 
> difference quotients of the analytical gradients. Please be aware that a 
> vibrational analysis requires a very accurate setup especially with your 
> required displacement. Your EPS_SCF is definitely too low for that, your 
> CUTOFF and the EPS_DEFAULT in the QS section could be also improved. The 
> general recommendation is a value 1.0E-7 to 1.0E-8 for EPS_SCF. You need 
> analytical gradients with an accuracy of several digits as too noisy 
> gradients will render the frequencies meaningless. The expected differences 
> in gradients should be at least one or two orders of magnitude higher than 
> the accuracy of the gradients.
> Best,
> Frederick
>
> Sihem AZIZI schrieb am Montag, 19. Mai 2025 um 20:46:26 UTC+2:
>
>> Dear all,
>>
>> I've been running a frequency calculation for over a month and it's still 
>> running. I don't know what's wrong. Can someone help me?
>> Best regards,
>> Sihem
>>
>

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