[Pw_forum] Re: Phonon frequencies different for equivalent q points

[stewart at cnf.cornell.edu]

Hi Paolo, 

  Thanks for the tip on the cartesian coordinates.  I had assumed the 
coordinates were in terms of reciprocal lattice vectors.  The results for M 
along the two directions now match. 

Best regards, 

Derek 

 

Paolo Giannozzi writes: 

> On Tuesday 11 April 2006 20:45, stewart at cnf.cornell.edu wrote: 
> 
>> I am looking at the high symmetry lines, Gamma-K-M along the [x,x,0]
>> direction going from [0,0,0] to [1,1,0]*(2pi/a) and the Gamma-M line
>> along the [x,0,0] going from [0,0,0] to [1/sqrt(3),0,0]*(2pi/a).
> 
> are you sure these are the correct high-symmetry lines? please note
> that phonon wavevectors must be supplied in cartesian coordinates 
> 
> Paolo
> -- 
> Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
> Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
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################################
Derek Stewart, Ph. D.
Scientific Computation Associate
250 Duffield Hall
Cornell Nanoscale Facility (CNF)
Ithaca, NY 14853
stewart (at) cnf.cornell.edu
(607) 255-2856