[Pw_forum] graphene phonon dispersion problem

[Mikiyas Tsegaye]

Dear all,

I get the following message after running a phonon dispersion  
calculation for graphite.

****************************************************************************************************
message from matdyn routine


Z* not found in file graphite.fc, TO-LO splitting at q=0 will be absent
A direction for q was not specified: TO-LO splitting will be absent

*************************************************************************

I thought the solution would be to include epsil = .true. in the ph  
input file, but that makes the calculation crash at that step. Also,  
I'm not quite sure what it means by "direction of q not specified". my  
q inputs in the matdyn.in file look fine (gamma-K-M-gamma) and they  
actually do produce a dispersion plot, but it has more branches than  
are physically allowed, and they are quite jagged.

I would appreciate some help. thanks in advance.

- Mikiyas Tsegaye
   University of Virginia, Dept of ECE
   Carlottesville, VA, USA 
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