[CPMD-list] Charged Surface

[Axel Kohlmeyer]

>>> "EK" == Eung-Gun Kim <eunggun.kim at chemistry.gatech.edu> writes:

EK> Dear List Subscribers,

EK> Would it be possible to model a charged surface (+1 or -1) using SURFACE
EK> (v3.9.1)?  My limited understanding of the original papers on an isolated
EK> charged cluster does not allow me to think beyond,  I have not been successful
EK> in finding papers on the extension of those methods to 1-D and 2-D.  Thanks very
EK> much for reading.

dear eg kim,

unlike in classical MD, with electron structure codes, you can
only set the _total_ charge of the system (i.e. how many electrons
you add to your system of (pseudo)atomic cores). so you have a problem
fixing the charge at the surface. in fact, the way i've seen it usually 
done is the other way around: you give the atomic structure, calculate
the electron structure, and then try to localize the electrons.

now for building surfaces you have to be aware, that you do a slab
calculation and therefore you have _two_ surfaces. a way to handle 
a charge defect at a surface via adding/removing/substituting an
atom at one surface, is to have the opposite defect at the 
opposite surface, so that the total system is neutral.
the poisson solver (via SYMMERTY 0 and SURFACE) should then care 
of cancelling the resulting dipole moment.

regards,
        axel kohlmeyer.


EK> Regards,

EK> EG Kim
EK> _______________________________________________
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EK> CPMD-list at cpmd.org
EK> http://cpmd.org/mailman/listinfo/cpmd-list



--

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Axel Kohlmeyer       e-mail: axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
D-44780 Bochum  http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.