On Mar 11, 2009, at 1:32 PM, Jeffrey Mullen wrote: > > Thanks for the recommendation. I have performed the calculation with > the > iverbosity set to 1. It will take me a while to parse it and > understand > the output, but if I can figure out the relationships, I will > attempt to > code the ordering into the application.
that would be really great! SB > > > Cheers > Jeff Mullen > North Carolina State University > > > Dal Corso Andrea wrote: > >> >> It is an interesting idea. I think it is possible to make the >> symmetry classification of the displacements patterns with the same >> routine that makes the symmetry classification of the eigenvectors >> of the dynamical matrix. Presently, this is not done. You can >> code this feature yourself or just use iverbosity=1. With this option >> the code writes the displacement patterns and you can >> check their symmetry. >> >> Andrea >> >> >> >> >> >>> Cheers >>> Jeff >>> >>> >>> >>> e kb wrote: >>> >>> >>> >>>> Dear Jeff, >>>> I am definitely not an expert on the topic but I'd like to >>>> understand >>>> your question better. >>>> >>>> Mode symmetry, D_6h(6/mmm) point group: >>>> >>>> omega( 1 - 1) = -37.4 [cm-1] --> A_2u I >>>> omega( 2 - 3) = -33.9 [cm-1] --> E_1u I >>>> omega( 4 - 4) = 863.3 [cm-1] --> B_2g >>>> omega( 5 - 6) = 1336.0 [cm-1] --> E_2g >>>> >>>> So you have the irr. representations and the values for omega >>>> (values >>>> are printed with higher precision in the previous part after >>>> diagonalization as you reported). What exactly do you want to know >>>> more (that you cannot check from a book on group theory) ? >>>> >>>> Emine Kucukbenli, grad. student, SISSA, Italy. >>>> >>>> --- On *Tue, 3/10/09, Jeffrey Mullen /<jtmullen at ncsu.edu>/* wrote: >>>> >>>> From: Jeffrey Mullen <jtmullen at ncsu.edu> >>>> Subject: [Pw_forum] Phonon branch enumeration >>>> To: pw_forum at pwscf.org >>>> Date: Tuesday, March 10, 2009, 2:34 AM >>>> >>>> Greetings >>>> >>>> I am testing electron-phonon interaction calculations with >>>> graphene and >>>> have encountered a problem enumerating the resulting phonon >>>> branches. >>>> When I run the ph.x calculation at the q(0 0 0), the code >>>> calculates 4 >>>> representations: >>>> >>>> Representation # 1 modes # 1 2 >>>> Representation # 2 mode # 3 >>>> Representation # 3 mode # 4 >>>> Representation # 4 modes # 5 6 >>>> >>>> >>>> When the values for omega are calculated, the results are: >>>> >>>> ************************************************************************** >>>> omega( 1) = -1.119851 [THz] = -37.354451 [cm-1] >>>> omega( 2) = -1.016557 [THz] = -33.908905 >>>> [cm-1] >>>> omega( 3) = -1.016557 [THz] = -33.908905 [cm-1] >>>> omega( 4) = 25.882237 [THz] = 863.344237 [cm-1] >>>> omega( 5) = 40.051667 [THz] = 1335.988701 [cm-1] >>>> omega( 6) = 40.051667 [THz] = 1335.988701 [cm-1] >>>> ************************************************************************** >>>> >>>> >>>> with the following mode symmetries: >>>> >>>> Mode symmetry, D_6h(6/mmm) point group: >>>> >>>> omega( 1 - 1) = -37.4 [cm-1] --> A_2u I >>>> omega( 2 - 3) = -33.9 [cm-1] --> E_1u I >>>> omega( 4 - 4) = 863.3 [cm-1] --> B_2g >>>> omega( 5 - 6) = 1336.0 [cm-1] --> E_2g R >>>> >>>> >>>> My question is one of ordering. How do I extract which omega(##) >>>> corresponds to which representation/mode? >>>> >>>> Thanks >>>> Jeff Mullen >>>> North Carolina State >>>> University >>>> >>>> _______________________________________________ >>>> Pw_forum mailing list >>>> Pw_forum at pwscf.org >>>> http://www.democritos.it/mailman/listinfo/pw_forum >>>> >>>> >>>> >>>> ------------------------------------------------------------------------ >>>> >>>> _______________________________________________ >>>> Pw_forum mailing list >>>> Pw_forum at pwscf.org >>>> http://www.democritos.it/mailman/listinfo/pw_forum >>>> >>>> >>>> >>>> >>> _______________________________________________ >>> Pw_forum mailing list >>> Pw_forum at pwscf.org >>> http://www.democritos.it/mailman/listinfo/pw_forum >>> >>> > > _______________________________________________ > 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090312/66355235/attachment-0001.htm
