[Pw_forum] electron phonon coupling of supercells

[Paolo Giannozzi]

On Oct 15, 2006, at 16:53 , luch001 wrote:

> I want to perform EPC calculation on a supercell.
>  Take NaCl as a example, I construct a 2*2*2 supercell
>  in the unit of primitive cell, whose space group is P1
>  with the lowest symmetry. We all know that the EPC
>  is a much time consuming process. Introducing symmetry
> operation to the system can speed the calculation greatly.

point symmetry is automatically calculated and exploited,
irrespective whether the unit cell is what one usually
calls "a supercell", or not. Translational symmetry is
dictated by the cell (or supercell). Of course the larger
the cell, the larger the computer time needed.

Paolo