If you want to compute electron-phonon interaction for a phonon of wavevector q, you will need electron wavefunctions at k and k+q. Thus your grid for scf should always be a multiple of your q-point grid for phonon calculations. Since 8 is a multiple of 2 and 4 but not 6, you are getting this error. Hope that helps. Sridhar Purdue University
On Sun, Jun 1, 2014 at 9:36 AM, Peram sreenivasa reddy < peramsreenivas at gmail.com> wrote: > Dear Pwscf, > > > In my phonon calculations i got some error. > > For nq1=2, nq2=2, nq3=2 and nq1=4, nq2=4, nq3=4 i did not get any errors. > > But for nq1=6, nq2=6, nq3=6 grid i got the bellow error. > > Diagonalizing the dynamical matrix > > q = ( -0.166666667 0.166666667 -0.166666667 ) > > ************************************************************************** > omega( 1) = 1.218152 [THz] = 40.633179 [cm-1] > omega( 2) = 1.218152 [THz] = 40.633179 [cm-1] > omega( 3) = 2.760322 [THz] = 92.074433 [cm-1] > omega( 4) = 3.157206 [THz] = 105.313054 [cm-1] > omega( 5) = 3.157206 [THz] = 105.313054 [cm-1] > omega( 6) = 3.160843 [THz] = 105.434373 [cm-1] > omega( 7) = 6.119555 [THz] = 204.126381 [cm-1] > omega( 8) = 6.129602 [THz] = 204.461528 [cm-1] > omega( 9) = 6.129602 [THz] = 204.461528 [cm-1] > omega(10) = 9.495441 [THz] = 316.733825 [cm-1] > omega(11) = 9.521102 [THz] = 317.589790 [cm-1] > omega(12) = 9.521102 [THz] = 317.589790 [cm-1] > ************************************************************************** > > Mode symmetry, C_3v (3m) point group: > > omega( 1 - 2) = 40.6 [cm-1] --> E L_3 > omega( 3 - 3) = 92.1 [cm-1] --> A_1 L_1 > omega( 4 - 5) = 105.3 [cm-1] --> E L_3 > omega( 6 - 6) = 105.4 [cm-1] --> A_1 L_1 > omega( 7 - 7) = 204.1 [cm-1] --> A_1 L_1 > omega( 8 - 9) = 204.5 [cm-1] --> E L_3 > omega( 10 - 10) = 316.7 [cm-1] --> A_1 L_1 > omega( 11 - 12) = 317.6 [cm-1] --> E L_3 > > ************************************************************************** > electron-phonon interaction ... > > > > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > from elphsum : error # 3 > q is not a vector in the dense grid > > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > > stopping ... > > > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > from elphsum : error # 3 > q is not a vector in the dense grid > > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > > This error came after completing my first q point. > > > Is this q grid is correct for the given k points mesh? > > Is it better to increase it to nq1=8, nq2=8, nq3=8. ? > > Thank you very much in advance. > > > > > > > > -- > *P.V.SREENIVASA REDDY* > > *Research ScholarDepartment of Physics * > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20140601/806fdbff/attachment.html
