Hi Miguel, Thank you for your quick response and advice. I agree that with the cheap cost of calculating phonon points once you have the IFC, a visual inspection of the plot is usually enough to order the phonon dispersion along a given symmetry line in the Brillouin Zone.
However, I would like to be able to sort the phonon frequencies for a large number of q-vectors in the Brillouin zone (not just restricted to a single symmetry line) and for this it would be very helpful if I can automate the process. I know that for electronic bands, it is possible to determine the symmetry character of a given electronic band using sym_band.f90. Would it be possible to use the same subroutines to determine the symmetry character of the phonon bands? I could then sort based on this output. If anyone has some thoughts on this, I would be very interested. Thanks, Derek ################################ Derek Stewart, Ph. D. Scientific Computation Associate ** New Webpage ** http://sites.google.com/site/dft4nano/ 250 Duffield Hall Cornell Nanoscale Facility (CNF) Ithaca, NY 14853 stewart (at) cnf.cornell.edu (607) 255-2856 Miguel Mart?nez wrote: > Dear Derek, > > I recently discovered that plotband.x is also able to plot phonon bands > as well as band structures. Just set all the references to 0. In any > case, if you have the IFC you shouldn't have issues distinguishing > crossing from anticrossing. Adding more points to the dispersion bands > is almost free, after all. At least it is in the smallish systems I've > done phonon calculations for. > > Regards, > > Miguel > > On Mon, 07 Dec 2009 13:42:50 -0500 Derek Stewart > <stewart at cnf.cornell.edu> wrote: > >> Hi everyone, >> >> I was wondering if anyone has written a script or program to sort the >> phonon frequencies based on their band index or branch. This would >> be very helpful for both plotting and post-analysis. Currently when >> you use matdyn for a given set of q-vectors, it prints out the phonon >> frequencies in order from lowest to highest. However, this does not >> take into account the possibility of band crossings which can lead to >> changes in the order of the bands. Matdyn also prints out the >> eigenvectors for the phonons so it should be possible to analyze this >> and then sort them. If someone has already addressed this issue, I >> would be very interested in any tools that can handle this. >> >> Thanks, >> >> Derek >> >> ################################ >> Derek Stewart, Ph. D. >> Senior Research Associate >> ** New Webpage ** >> http://sites.google.com/site/dft4nano/ >> 250 Duffield Hall >> Cornell Nanoscale Facility (CNF) >> Ithaca, NY 14853 >> stewart (at) cnf.cornell.edu >> (607) 255-2856 >> >> >> >> >> >>