[Pw_forum] ion problem

[Axel Kohlmeyer]

On Wed, 14 Nov 2007, Rudra Banerjee wrote:

RB> dear PWSCF users,

dear rudra,

RB> I am new to pwscf and stuck in a question......is there any way 
RB> toput anion or cation as a unit?the total cluster is charge less but 
RB> have two different types of ion.......can anyone tell me what to do 

let me guess: you did classical MD before?
in a first principles calculation, there is usually no
need to distinguish between atoms and ions. you put in
the core charges (as point charges or pseudopotentials)
and then add the proper number of electrons, and the
QM calculation (in DFT approximation when using PWSCF)
will take care of how the electrons are distributed.

so you only have to take care of the total charge,
because it determines in combination with the sum
of the core charges how many electrons need to be added.

HTH,
  axel. 

RB> in this situation?

Regards
 
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Rudra
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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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