[Pw_forum] Documentation for fd_ef.x

[Lorenzo Paulatto]

On 02/25/2018 07:58 PM, Robert Wexler wrote:
> force constants. Since ph.x, to the best of my knowledge, cannot handle 
> vdW corrections, 
 > ... QE version 5.1.

The current version ph.x can handle vdW corrections with no problems, 
but you'll have to upgrade, because v5.1 is very old.

To get epsilon doing finite derivatives from modern theory of 
polarization, via fd_ef, or not by hand, the only difficulty are the 
units of measure, is not very efficient it would probably take a billion 
k-points. If you insist, and manage to do it, please send us a working 
example.

hth


-- 
Lorenzo Paulatto - Paris