[Pw_forum] the high symmetry line of BCT phonon dispersion band structures

[Paolo Giannozzi]

You can set ibrav=0 and choose the lattice vectors you want

Paolo


On Tue, 2014-12-16 at 01:22 +0530, Kondaiah Samudrala wrote:
> Dear all,
> 
> 
> I am still confused with notation of Ibrav=7 in pwscf. The IBRV=7
>  primitive cell vectors in pwscf are quite different from any other.
> See below for two cases of primitive vectors IBRAV=7
> Case1
> For. e.g. In pwscf primitive vectors of IBRV=7 are
>      crystal axes: (cart. coord. in units of a)
>                a(1) = (   0.500000  -0.500000   c/a)  
>                a(2) = (   0.500000   0.500000   c/a )  
>                a(3) = (  -0.500000  -0.500000   c/a )  
> Case 2
> On the other hand, generally people used as (from published papers)
>      crystal axes: (cart. coord. in units of a)
> 
>                a(1) = (  -0.500000  0.500000    c/a)  
>                a(2) = (   0.500000   -0.500000   c/a )  
>                a(3) = (   0.500000   0.500000   -c/a ) .
> 
> 
> This variation leads to changes in reciprocal vectors and then IBZ
> path. From Wikipedia
> (http://www.sciencedirect.com/science/article/pii/S0927025610002697)
> and http://www.cryst.ehu.es/ , I obtained the IBZ path for case 2.
> But, what about the IBZ path of case 1 primitive cell vectors??  Is
> both are same ??? But Xcrysden showing something else than regular
> Gamma, Z, Sigma, P and N points .
> 
> 
> I feel puzzled, would some one give some idea about this? any help will be appreciated
> with regards
> S. Appalakondaiah
> PhD Student
> University of Hyderabad
> 
> 
> 
> 
> 
> 
> 
> 
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum

-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222