Re: [Pw_forum] Negative freuqencies for extrapolating points

Dear Professor Paulo and Fransesco, thanks for your help and suggestions From: pw_forum-boun...@pwscf.org on behalf of Paolo Giannozzi Sent: Thursday, August 25, 2016 12:41 PM To: PWSCF Forum Subject: Re:

Re: [Pw_forum] Negative freuqencies for extrapolating points

I am aware of other cases in which acoustic phonon frequencies close to q=0 behave in a funny way. It happens in very small regions and resists to standard attempts (increasing convergence etc.) to get rid of it. No explanation and no fix available for now. Paolo On Thu, Aug 25, 2016 at 4:03 PM,

Re: [Pw_forum] Negative freuqencies for extrapolating points

In my experience, increasing also the convergence for forces and total energy of the scf cycle you perform before the neb.x run, helps a lot to clean negative frequencies. Then, all other cutoffs and settings that increase amount of memory and cpu time, can helps, sometimes significantly,

[Pw_forum] Negative freuqencies for extrapolating points

Dear all, I have calculated the frequencies for a structure. All frequencies were positive except for a few "extrapolated" points very close to the Gamma point which were negative in the range of -1.45 cm^-1. Due to this the dispersion curve near the Gamma point looked a bit funny (but looks

Re: [Pw_forum] Error has not been solved

Actually it is not that simple: apparently one of the values for DFT, either read from pseudopotentials or provided in input, has a malformed syntax. Paolo On Thu, Aug 25, 2016 at 2:21 PM, stefano de gironcoli wrote: > Dear Mohammadreza, > the error means that you are

Re: [Pw_forum] Error has not been solved

Dear Mohammadreza, the error means that you are using two pseudo-potentials that have been generated with two different functionals. in particular the gradient corrected functional for exchange appears to be in conflict. check your pseudo-potentials stefano On 25/08/2016 14:00,

[Pw_forum] Error has not been solved

Dear giannozzi I studied your message about my error " conflicting igcx value " but i could not see this part at my pseudo file. What variables are conflicting exactly ? Best mohammadreza___ Pw_forum mailing list Pw_forum@pwscf.org