Re: [Pw_forum] Phonon negative Frequency

Dear All, Thank you all for your kind reply. >From all of your reply, I understood one could not know negative frequency while the phonon program is running till it's end whether it is running in parallel mode or in serial mode. I also understand one has to take precautions while

Re: [Pw_forum] Phonon negative Frequency

Dear Suresh, Adding to the comment of Isaiah, did you check the FAQ? http://www.quantum-espresso.org/faq/phonons/#7.3 Greetings, apsi PS Why running in serial...? I guess basically any CPU nowadays has at least two cores.

Re: [Pw_forum] Phonon negative Frequency

Hi1- Use parallel version2- A bad converged structure (with low threshold) may give large negative phonons.3- Use very tight SCF convergence Regards David On Wednesday, November 29, 2017, 10:42:44 AM GMT+3:30, Suresh A wrote: Dear All, I

Re: [Pw_forum] Phonon negative Frequency

Dear Suresh, unfortunately, there is no way to know this before - or at least I don't know of any. Yet, you'll nearly always have 3 negative frequencies at the Gamma point which should actually be zero. Furthermore, it is really important that you relax your system really carefully before

Re: [Pw_forum] Phonon negative Frequency

Dear Suresh, I doubt if there is any way you can know if you'll have negative frequency while the calculation is on. However you can take note of some of the information in phonon user's guide on how to avoid negative frequency. Also, you can do a test run with a single q-point splitted among

[Pw_forum] Phonon negative Frequency

Dear All, I am ran phonon calculation for anatase previously and got negative frequencies. I was install QE-5.2.0 in serial mode and took days to finish the calculation in my desktop. Is there any way to know the negative frequency before the calculation ends? So that the time can be