[Pw_forum] chargedensity

[Lorenzo Paulatto]

On Wed, August 5, 2009 12:38, vamsi kv wrote:
>  1. Can i print the chargedensity information after every iteration in the
>  scf or relax calculation? or can we know waht is the initial charge
>  density gues and how it changes during the simulation.

Not without modifying the code; I wouldn't take too much effort to program
it, but you'll need a good reason if you wish someone to do it for free
;-).

The initial charge density is a superposition of atomic charge densities
(as defined in the pseudopotential file), if necessary renormalized (in
Fourier space, e.g. rescaling the G=0 component)

>  2.  What is bonding chargedensity?

The fraction of charge density that cannot be assigned to a specific atom.
It is an ill defined quantity in plane-wave based codes (such as
quantum-espresso). Actually I think it is an ill defined quantity in every
code, although it helps chemical intuition.

Computing maximally-localized Wannier functions, to see which are centered
far off the ions, is probably more meaningful.

regards

-- 
Lorenzo Paulatto
SISSA  &  DEMOCRITOS (Trieste)
phone: +39 040 3787 511
skype: paulatz
www:   http://people.sissa.it/~paulatto/



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