[QE-users] About matdyn.x and choice of "selected lines"

[patrizio.graziosi at cnr.it]

Hello everybody,

in the example03 about the calc. of e-ph coupling in FCC aluminum,
https://github.com/QEF/q-e/tree/master/PHonon/examples/example03,
at a certain point it writes

5) Calculate gamma on selected lines using "matdyn.x" (dos=.false.)

and in the input files these "selected lines" are indicated as follows:

19
   0.000 0.0 0.0     0.0
   0.125 0.0 0.0     0.0
   0.250 0.0 0.0     0.0
   0.375 0.0 0.0     0.0
   0.500 0.0 0.0     0.0
   0.750 0.0 0.0     0.0
   1.000 0.0 0.0     0.0
   0.825 0.125 0.125 0.0
   0.750 0.250 0.250 0.0
   0.625 0.375 0.375 0.0
   0.500 0.500 0.500 0.0
   0.325 0.325 0.325 0.0
   0.250 0.250 0.250 0.0
   0.125 0.125 0.125 0.0
   0.000 0.000 0.000 0.0
   0.125 0.125 0.000 0.0
   0.250 0.250 0.000 0.0
   0.325 0.325 0.000 0.0
   0.500 0.500 0.000 0.0


I kindly ask you:
1. How the lines are identified, do they draw a path connecting each  
point or they start from Gamma and reach each point, or...?
2. How to identify these lines in metals with a different structure,  
example hexagonal hcp, or in the case the Fermi surface is different  
from the one of aluminum even fr the same symmetry?

Thanks in advance

Patrizio

-- 

Patrizio Graziosi, PhD

Research Scientist

CNR - ISMN
Institute for the Study of Nanostructured Materials