Hello all, For the phonon dispersion calculation, I've done the convergence test by 'vc_relax' calculation and re-assigned the lattice parameters (celldm(1), celldm(4), conv_thr, and ATOMIC_POSITIONS). However, my phonon dispersion still behave a bit weird (negative acoustic frequency, LO-TO splitting).
My structure is very complicated, rhombohedron with 5 basis, and now I guess it might be the convergence threshold (tr2_ph). My 'tr2_ph' has been set as '1.0d-14' I am looking for the way of finding a proper tr2_ph value. Is there any convergence test for that? My simulation would run more than 50 hrs, so I don't want to just give it a shot with randomly picked value. Thanks as always. Best, Kyeong -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20121102/46a5a9fe/attachment.html
