Dear all, I am performing phonon dispersion calculations for AB2 type Body centered tertagonal structure with lattice parameters a= 4.315 and c =6.990. While performing SCF calculations, I used 10 X10 X7 k grid and i got all forces are <10-5 eV/atom. After that, I used 4X4X3 q grid for phonon dispersion, my o/p says symmetry breaking, where as If i am using 4 X4 X 4 q-grid my phonon dispersion shows imaginary frequencies at acoustic phonons.
Pls help me in choosing Kpoint and qpoint grids for any crystal structures(except cubic). with regards S. Appalakondaiah University of Hyderbad Hyderbad -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20131219/d5d6b958/attachment.html
