[Pw_forum] convergence NOT achieved after 100 iterations --- related question

[Hande Ustunel]

Dear PWSCF community,

While we are on the subject of convergence, I would like to inquire about
something that we have consistently been observing in a very large number
of the systems we have studied (examples being metal atoms on g-Al2O3, CeO2
surfaces etc). While gaussian smearing consistently produces convergence
without problems at first shot for a smearing width of 0.01-0.02, we
frequently have problems with mv smearing (our favorite) for the same
width. Systematically exploring a giant portion of 6 or 7-dimensional
parameter space (kpoints, smearing width, vacuum length so forth)
eventually results in convergence with mv but we usually have to fiddle a
lot; with gauss instead, anything basically works. Would anyone be able to
confirm this experience or better still provide some insight on the
realtive ease of using mv vs gauss?

Thank you very much in advance.
Best regards,
Hande Toffoli


--
Hande Toffoli
Department of Physics
Office 439
Middle East Technical University
Ankara 06531, Turkey
Tel : +90 312 210 3264
http://www.physics.metu.edu.tr/~hande