[CP2K-user] [CP2K:16495] Re: IR spectm for NaCl under PBC

[Victor Volkov]

Dear Fabian;
excellent!
Great learning.
Thank you.
With best regards,
:-)
Victor

On Mon, Jan 24, 2022 at 4:22 PM fabia... at gmail.com <fabianducry at gmail.com>
wrote:

> Dear Victor,
>
> You need a much tighter convergence criterion for the optimization prior
> to the vibrational analysis. You increased MAX_FORCE to 5e-3 (guessing
> from the output), instead you have to decrease it to at least 1e-5, maybe
> even lower.
> CP2K prints the forces for the replica in the output. The forces under
> "Minimum Structure - Energy and Forces:" should be more or less 0 and
> considerably differ between the other images. Currently you are computing
> the vibrational analysis from almost pure noise.
>
> Cheers,
> Fabian
> On Sunday, 23 January 2022 at 19:58:05 UTC+1 volk... at gmail.com wrote:
>
>> Dear colleagues:
>> here is the normal mode analysis I could manage by now for NaCl under PBC.
>>
>> There is only one unit cell: previously, I reported that I could not
>> configure CP2K to reproduce NaCl structure using multiple cells 2 2 2.
>> There are strange distortions, which I did confirm to sustain under
>> different CUTOFF values (1000 and 600), and regardless if dispersion is
>> switched off or not.
>>
>> When a single cell under PBC, optimization leads to the “right”
>> structure, when ESP 10^-12.
>>
>> However, the negative(imaginary) frequencies are many and they are very
>> large.
>> I may anticipate that the “miss performance” is enhanced due to the PBC.
>>
>> Eventhough the results are "devastating",
>> :-)
>> nonetheless, I find this might be very good, very helpful – I got an idea.
>>
>> Dear Dr. Hutter,
>> is it possible that CP2K may have an “issue” about positioning a
>> structure
>> in respect to both, in respect to the FT grind and in respect to the PBC.
>> Perhaps, there could be a relative mismatch phenomenon, which could
>> stimulate artificial transition states with negative frequencies?
>>
>> May be, what I observe is that PBC on the unit cell helps to sense this
>> better?
>>
>>
>> Thank you for your time and for any comments.
>>
>> With best regards,
>> Sincerely
>> Victor
>>
> --
> You received this message because you are subscribed to a topic in the
> Google Groups "cp2k" group.
> To unsubscribe from this topic, visit
> https://groups.google.com/d/topic/cp2k/bAo0CtNixo8/unsubscribe.
> To unsubscribe from this group and all its topics, send an email to
> cp2k+unsubscribe at googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/cp2k/dd5077c3-4bac-4fa0-a81d-ef779f43e157n%40googlegroups.com
> <https://groups.google.com/d/msgid/cp2k/dd5077c3-4bac-4fa0-a81d-ef779f43e157n%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
>

-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/CAK%2B-SShH1L1nFdKgqpJbayAnJJiTqPz21AeGXWW1qVLvRNshtA%40mail.gmail.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20220124/796869a8/attachment.htm>