[CPMD-list] Neutralize the excess charge in CPMD

[Juerg Hutter]

Hi

if there is a net charge in your system CPMD takes care
of this depending on the Poisson solver used.
For periodic systems a neutralizing background charge is
added (no keyword option is needed, this is done automatically).
If you use a Poisson solver for isolated systems (Hockney or
Tuckerman) then the background charge is not needed.
These methods calculate correctly the G=0 term of the
potential. This is explained in the original papers
or in the review at
D. Marx and J. Hutter published in Modern Methods and Algorithms of
Quantum Chemistry, Forschungszentrum Jülich, NIC Series, Vol. 1 (2000),
301-449
http://www.fz-juelich.de/nic-series/Volume1/

regards

Juerg Hutter

----------------------------------------------------------
Juerg Hutter                   Phone : ++41 1 635 4491
Physical Chemistry Institute   FAX   : ++41 1 635 6838
University of Zurich           E-mail: hutter at pci.unizh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
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On Tue, 5 Apr 2005, Jiten wrote:

> Dear CPMD users,
>
> In few limited papers related to CPMD for excess charged systems, it hardly explain about the use of neutalizing the excess charge, a uniform background opposite charge are added to the system.
>
> I look at the CPMD manual as well, there is no section describing this option.
>
> I am just wondering whenever we do CPMD MD for the charged systems using box type of HOCKNEY Method or TUCKERMAN Method, are we taken cared to neutralize the excess charge.
>
> Could anyone suggest a reference and how can I deal with CPMD related to this.
>
> Sincerely,
>
> N. Jiten Singh
> C/O Prof. Kwang S. Kim
> Department of Chemistry
> Pohang University of Science and Technology
> San 31, Hyojadong, Namgu
> Pohang 790-784, Korea
> Phone : 82-54-279-5853 ( Lab ) / 279-4138 ( Appt )
> Fax : 82-54-279-8137 (or +82-54-279-3399)
> Web : http://csm.postech.ac.kr/ and http://www.postech.ac.kr/e
> Home Page : http://www.geocities.com/njs_19