Hi All, I have a query regarding selecting the size of q-grids to use when trying to obtain phonon dispersion. Obviously there is a difference between k-mesh and q-mesh as they are used to calculate different properties, as referenced in this thread from 2012: http://qe-forge.org/pipermail/pw_forum/2012-January/097425.html.
However my question is, how do we know the quality of a q-mesh that we have selected? Is that simply from the phonon dispersion and asking matdyn to calculated frequencies at a phonon point not in the grid then checking to see how well it fits, or is there another way where complete phonon frequencies do not have to be calculated to determine the quality of a q-mesh? Also adding onto that, when selecting a q-mesh how does one go about it? Is it ok to simply use the same grid size as that of the k-mesh (if not, how come?) and can the size of the k-mesh used give any clues as to what size q-mesh to use? Best, Apoorv Jain PhD Student Department of Chemical Engineering and Biotechnology University of Cambridge _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
