[CPMD-list] background charge

[Juerg Hutter]

Hi

you might either use an external potential defined
on the real space grid and given in a file or
alternatively you can add zero-electron pseudopotentials
to the system.
In both cases you have to be very careful. Due to the
fact that plane waves are completely unbiased, the use
of unscreened point charges might leed to stable
unphysical solutions.

regards

Juerg Hutter

----------------------------------------------------------
Juerg Hutter                   Phone : ++41 44 635 4491
Physical Chemistry Institute   FAX   : ++41 44 635 6838
University of Zurich           E-mail: hutter at pci.unizh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
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On Sat, 14 Apr 2007, Weijie HUA wrote:

> Dear All,
> I'd like to ask if CPMD can do calculations on systems added with background point charges.
>
> I have checked the manual and original pipemails, but didn't find topics on background charges.
> However,I found many discussions on EXTERNAL POTENTIAL which makes it possible to add an external
> electrostatic field. I'd like to ask can this keyword be used to add background point charges?
> If possible, how?
>
> Many thanks.
>
> Best regards,
> Weijie
>
>
>
> ----
> Weijie HUA, Ph. D. candidate
> Institute of Theoretical and Computational Chemistry,
> Key Laboratory of Mesoscopic Chemistry,
> School of Chemistry and Chemical Engineering,
> Nanjing University,Nanjing 210093,
> P.R.China
> Email:huawj at itcc.nju.edu.cn
> 2007-04-14
>
>
>