[Pw_forum] Image-charge interaction in dynamics

[Ilya Ryabinkin]

Dear colleagues:
I am trying to set up a charged molecule (anion) dynamics on a
metallic surface. To avoid dealing with a charged system, I'm using
specifically generated PP, which is produced from a core-hole state of
a target atom. In particular, to represent a Cl- anion, I generate PP
from the configuration
    [He]2s 2p5 3s2 3s6,
which has the valence configuration of Ar as it should be for a Cl- anion.

However, having moved one charge into PP I lose an important part of
electrostatic interaction: the interaction of an anion with its
electrostatic image inside a metal slab. I would like to bring this
piece back---at least at the level of dynamics---by adding forces that
come from a potential -1/z, where z = 2 is a normal distance of Cl- to
the surface.

I know this sort of correction is implemented in VASP (as I've deduced
form a publication), but I didn't find this in documentation.

Would it be possible to do the same in QE? I could also implement this
it if someone could help me where to start with.

A similar, but more sophisticated strategy is discussed here:
http://dx.doi.org/10.1088/0953-8984/25/35/355006
Potentially, I can implement this as well, but I'd like to be sure
that it would be interesting not only for me.


Thanks in advance,
I.


-- 
*******************************************************
                    Ilya Ryabinkin
                 Postdoctoral Scholar
          Physical and Environmental Sciences
           University of Toronto Scarborough
  http://www.utsc.utoronto.ca/~aizmaylov/Members.html
*******************************************************