Dear Sir, I Completed the Phonon calculations with IBRAV=7 option...Its quite difficult to reperform the calculations. Can you please provide the IBZ path or source for obtain the IBZ???
with regards S. Appalakondaiah PhD student University of Hyderabad On Tue, Dec 16, 2014 at 1:22 AM, Kondaiah Samudrala <[email protected] > 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/ > <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 > > > > > >
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