surface dipole correction:applicability/universality

[Victor Volkov]

Dear users and developers

I wish to ask if this command

SURFACE_DIPOLE_CORRECTION T
SURF_DIP_DIR Z

Is this a universal MUST whenever we model ANY surface

under PERIODIC XYZ?

(I assume, this is not important under PERIODIC XY.)

May I state that

this is important for a metal surface (electronic delocalizations)

where an adsorbed molecule (on the top)

is symmetric in respect to X and Y

but not in respect to Z: like, OH anion under the vertical orientation?

How important

SURFACE_DIPOLE_CORRECTION T

should be if one would model systems like

2-3 layered graphite,

where the layers are well separated and barely "feel" each other (see attached),

or

2 layer silica with a disordered water cluster at the top,

hence, there is no obvious symmetry and, due to the nature of atoms,

charges are rather localized (see attached).

This is about, how universal is this article

https://journals.aps.org/prb/abstract/10.1103/PhysRevB.59.12301

in the applications as programmed by cp2k.

Thank you.

Happy 2022 for every cp2k

:-)

Victor

[Marcella Iannuzzi]

Dear Victor 

The importance of the dipole correction depends on the electrostatic properties of the system. 

For instance in order to determine the workfunction from an asymmetric slab it is needed. 

On the other hand, for electrostatic ally symmetric system has no effect. 

Just compute energy and forces  with and without dipole correction to estimate its contribution for the specific system of interest.

Regards 

Marcella

[Victor Volkov]

Dear Marcella:

thank you very much.

With best regards,

Victor

--
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+uns...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/4f7828e9-042f-4501-b13a-2989aa1acaa1n%40googlegroups.com.