[Pw_forum] How to calculate charge density difference

[Clark Lee]

A difference plot can be  obtained by subtracting from a total system(e.g.
an adsorbate on surface) the densities of each seperated system (e.g., the
adsorbate, clean surface), keeping atomic position the same.This is very
similar to the method of calculating an adsorption energy


On 11/9/06, Xiangmei Duan <duan at physics.usyd.edu.au> wrote:
>
>
> for details see INPUT_CHDENS
>
>    !----FOR i = 1, nfile:
>    !
>    !      filepp(i)   file containing the 3D charge (produced by pp.x)
>    !                  (AT LEAST filepp(1) REQUIRED)
>    !      weight(i)   weight - The quantity to be plotted will be
>    !                  weight(1)*rho(1) + weight(2)*rho(2) +
> weight(3)*rho(3)+...
>    !                  (OPTIONAL: default weight(1)=1.0)
>    !
>    !                  BEWARE: atomic coordinates are read from the first
> file;
>    !                  if their number is different for different files,
>    !                  the first file must have the largest number of atoms
> For your case, you have 3 files, with the weights 1.0 dor infterface, and
> -1.0 for surface I and II.
>
> Hope it helps,
> Xiangmei
>
> On Thu, 9 Nov 2006, Chaohao Hu wrote:
>
> > Dear pwscf users,
> >
> > I have known that charge density difference (CDD) can be used to
> > explain charge transfer and bonding characteristic in many
> > references. But how to calculate it in pwscf code. I know
> > pwscf can calculate charge density (CD) directly. For the interface
> > including surface I and II, can we solve this problem as the
> > following way:
> > ==================================
> >  CDD(interface) = CD(interface) - CD(surface I) - CD(surface II)
> > ==================================
> > Certainly, the interface and suface I and II all maintain the same cell
> > shape. Is it right?
> >
> > Can someone give more details or hints on it? I would appreciate your
> > great help.
> >
> > Thanks in advance.
> >
> > Best regards,
> > Chaohao
> >
> > ============================================================
> > Dr.Ch.H.Hu
> > Institute of Metal Research,Chinese Academy of Sciences--IMR
> > Wenhua Road, 72
> > 110016, Shenyang, Liaoning (China)
> > Phone: +086-024-23971641
> > Email: chhu at imr.ac.cn
> >
> >
> >
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> >
>
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-- 
Standing on the shoulders of Newton
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