Dear Stefano, Thank you very much for the suggestion. I'll see what I can find regarding the vibrational Wannier functions and I will be glad to report back if I come across some interesting options.
Regards, 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 Stefano Baroni wrote: > Derek: I do not think/know that/if anything is implemented already, > but you problem was elegantly addressed some time ago by Karin Rabe > who introduced the concept of "vibrational Wannier function" (or > something like that). You may want to browse the literature and report > to us if you find anything meaningful/interesting. I maintain, though, > that the process you want to automate can be automated using IFC as > well. Cheers - Stefano > > On Dec 8, 2009, at 4:07 PM, Derek Stewart wrote: > >> 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 >>>> >>>> >>>> >>>> >>>> >>>> >> >> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum > > --- > Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste > http://stefano.baroni.me [+39] 040 3787 406 (tel) -528 (fax) / > stefanobaroni (skype) > > La morale est une logique de l'action comme la logique est une morale > de la pens?e - Jean Piaget > > Please, if possible, don't send me MS Word or PowerPoint attachments > Why? See: http://www.gnu.org/philosophy/no-word-attachments.html > > > > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >