[Pw_forum] pseudopotential for ions

[Stefano Baroni]

Giacomo: if the pp is good (technically, one says "transferable") it is 
supposed to work in any "reasonable" chemical environment. That's what 
pp's are designed for! On the other hand, if a given complex turns out 
to be charged or not, it is not you who decide, but the charge 
rearrangement determined by self consistency. Of course, the pp is an 
input o such a procedure, and it cannot be made depend on the output!

In summary, read some literature (even old one) on on pp's, and then 
enjoy your simulations!

Yours  Stefano B.

On Oct 8, 2004, at 6:17 PM, Giacomo Saielli wrote:

> Dear developers and users,
>  I am planning to run a Car-Parrinello simulation with cp.x module 
> using Vanderbilt PP for a system containing some water and 
> acetonitrile molecules plus one charged tetramethylammonium ion.  I 
> wonder if there could be any problem in using the same PPs I use for 
> the atoms of the neutral molecules also for the atoms of the charged 
> TMA ion, or if I should build special ultrasoft PPs for the TMA atoms. 
> I would appreciate any comment on this.
>  Thank you very much,
>  best wishes,
>  Giacomo
>
> -- 
> Giacomo Saielli
> Istituto per la Tecnologia delle Membrane del CNR, Sezione di Padova;
> Via Marzolo, 1 - 35131 Padova, Italy;
> Tel: +39-049-8275279; Fax: -5239;
> http://www.chfi.unipd.it/home/g.saielli/
>
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---
Stefano Baroni    ---  SISSA  &  DEMOCRITOS National Simulation Center
via Beirut 2-4 34014 Trieste Grignano / 
[+39] 040 3787 406 (tel) -528 
(fax)

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