 
 
 
 
 
 
 
  
When you perform a calculation of electron-phonon interaction coefficients with the tetrahedron method, you have to use an offset q-point grid in order to avoid a singularity at q = Γ; you can perform this calculation as follows:
occupation = "tetrahedra_opt" and K_POINT automatic.
lshift_q = .true. and electron_phonon = "" (or unset it)
    to generate the dynamical matrix and
    the deformation potential (in _ph*/{prefix}_q*/) of each q.
electron_phonon = "lambda_tetra".
    You should use a denser k grid by setting nk1, nk2, and nk3.
    Then lambda*.dat are generated; they contain 
λqν.
alpha2f.x with an input file as follows:
&INPUTPH ! The same as that for the electron-phonon calculation with ph.x : / &INPUTA2F nfreq = Number of frequency-points for a2F(omega), /Then λ, and ωln are computed and they are printed to the standard output. α2F(ω) and (partial) phonon-DOS are also computed; they are printed to a file prefix
.a2F.dat.
There is an example in PHonon/example/tetra_example/.