[QE-users] Different results for charged cluster in PHonon 5.1 and 7.2

[RABONE Jeremy]

Hello,


  That's the thing - the calculations run as they should, everything is apparently as it should be but the frequencies are shifted significantly. I have done a few other tests of other charged clusters and H2O vs H3O+ and comparison with finite differences calculations and it genuinely seems that some correction for charged cells that was originally applied in PHonon is no longer applied.


It is no great problem since these calculations are fine using finite differences, but I was just curious as to what has happened and whether it was intentional (i.e. should calculations that were done using the old version be considered more approximate).


Kind regards,


Jeremy


________________________________
De : users <users-bounces at lists.quantum-espresso.org> de la part de Lorenzo Paulatto <lorenzo.paulatto at cnrs.fr>
Envoyé : mercredi 14 février 2024 17:23
À : users at lists.quantum-espresso.org
Objet : Re: [QE-users] Different results for charged cluster in PHonon 5.1 and 7.2


Hello,

On top of what Paola says, I would recommend checking the output of pw.x first. If the total energy calculation is not identical, the phonons results will be widely different. And if there is a difference in the total energy calculation, it could be traced back more easily to a change in the code.

kind regards.


On 14/02/2024 11:14, RABONE Jeremy wrote:

Hello,


  I have re-run a Phonon calculation for a charged cluster that was done using version 5.1 with version 7.2 and the results are completely different; there is a large positive shift in the frequencies. Can somebody tell me what was done differently in 5.1 for charged cells ?


Kind regards,


Jeremy Rabone



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