! Then, if (.not.dos) : ! nq number of q-points ! (q(i,n), i=1,3) nq q-points in 2pi/a units ! If q = 0, the direction qhat (q=>0) for the non-analytic part ! is extracted from the sequence of q-points as follows: ! qhat = q(n) - q(n-1) or qhat = q(n) - q(n+1) ! depending on which one is available and nonzero. ! For low-symmetry crystals, specify twice q = 0 in the list ! if you want to have q = 0 results for two different directions ! Anyway, you should specify 2 directions like
x(1) y(1) z(1) ........ x(N-1) y(N) z(N) 0 0 0 !!!!! Gamma point x(N)=0 y(N)=0 z(N)=0 x(N+1) y(N+1) z(N+1) ......... x(M) y(M) z(M) For a hexagonal lattice you could try A (00z) --> G(000) --> K(-1/3,2/3,0), as example. Hope this helps. Bests, Eyvaz. ------------------------------------------------------------------- Prof. Eyvaz Isaev, Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden Condensed Matter Theory Group, Uppsala University, Sweden Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se, eyvaz_isaev at yahoo.com --- On Thu, 4/16/09, Li YL <ylli at theory.issp.ac.cn> wrote: > From: Li YL <ylli at theory.issp.ac.cn> > Subject: [Pw_forum] propagation direction in the input file for dynmat.x > To: "pw_forum" <pw_forum at pwscf.org> > Date: Thursday, April 16, 2009, 4:05 PM > Dear all users, > > Now I've a question on the polar materials. In order to > get LO-TO splitting, you know, we need to use dynmat.x. In > the input file for dynmat.x, we need input q(1), q(2), and > q(3), that is, the propagation direction. I don't know > how to choose this direction. My system has hexagonal > symmetry and its primitive cell is rhombohedral. > Any suggestions are welcome. Thanks in advance. > > Bests, > > Yanling Li, > > Institute of Solid states physics, CAS, P. R. China. > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum
