[Pw_forum] query on fermi energy

[Ajit Vallabhaneni]

Dear users,

          1.  I was wondering how to calculate the absolute value of fermi energy for graphene single layer. By varying the size of the super cell in the out of plane direction, i observed that the total energy is constant indicating no  interactions in the out of plane direction, but the fermi energy is varying with increasing distance. I think it is the relative fermi energy which is output after the scf calculation. I want to know the absolute value. 

             
           2.  Another question i have is regarding the e-ph calculation. For a give set of q and k points, what is the best way to ensure that all k+q points are available to avoid the message " q is not a vector in the dense grid" in the calculations"? I observed that using a dense grid is not enough sometimes. Do we have to check it outside of the quantum espresso before the calculation begins? 


Thanks
Ajit