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["Erik Ylvisaker" <eylvisaker@physics.ucdavis.edu>]

Yes, it is necessary to include the resulting k-points as q-points if you want to generate phonon band structure or thermodynamic properties.  The file trf2_2.in generates k-points in the irreducible wedge of the Brillouin zone, which, by symmetries, allows one to have information on a regular grid in the entire Brillouin zone.  If you are missing points in the irreducible zone, the use of anaddb will error out with a message about missing DDB blocks.

 

You can change the ngkpt variable in trf2_2.in to increase or decrease the number of k(q) points you get out of it.  Lowering it to 2 2 2 might be a good way to start and see that your calculations finish ok.  But you should increase it and check the convergence of your results with respect to the q-point mesh.

 

----- Original Message -----

From: ha sa

To: forum abinit

Sent: Monday, October 16, 2006 5:35 AM

Subject: [abinit-forum] q vectors

Dear abinit users,

  in the second lesson on response functions, there is a suggested way to get the q wavevectors namely using trf2_2.in . Is it necessary to include all the resulting kpoints (as q points of course) in trf2_1.in to generate the DDBs.if not will that cause any trouble following the tutorial to get the phonon band structure.

 

regards

Hanan

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