A final question about that! Is there a way to check the frequencies of the Irreducible representations once each one is done or one has just to wait for the whole vibrational modes calculations to finish; The reason i am asking this is that since one might get negativefrequencies , I was wondering if I can check that before the whole calculation terminates (which takes 25 days) so I then can see what the problem is and lower the threshold if it is what is going wrong. Are those frequencies written to a file other than the output one? Thanks Elie
Date: Mon, 14 May 2012 09:45:53 +0200 Subject: Re: [Pw_forum] Irreps and vibrational modes From: [email protected] To: elie.moujaes at hotmail.co.uk On Mon, May 14, 2012 at 4:07 AM, Elie M <elie.moujaes at hotmail.co.uk> wrote: (1) Are all the modes vibrational? No, at Gamma you always have 3 translational modes of zero energy (2) Are any modes missing from the calculation like optical or accoustical modes? No (3) i did the calculation and got two of the modes negative which means either threshold is high or the ecutwav must be at least eight times ecutrho. Is a threshold of 10^(-15) still too high for such a system? This is FAQ2 for phonon calculations: http://www.quantum-espresso.org/?page_id=366#7.2 Thanks ElieUniversity of NottinghamNG7 2RDUK _______________________________________________ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -- Lorenzo Paulatto IdR @ IMPMC/CNRS & Universit? Paris 6phone: +33 (0)1 44275 084 / skype: paulatzwww: http://www-int.impmc.upmc.fr/~paulatto/ mail: 23-24/4?16 Bo?te courrier 115, 4 place Jussieu 75252 Paris C?dex 05 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120519/d32f97cc/attachment.htm
