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[Josef Zwanziger <jzwanzig@gmail.com>]

Comments are in-line with the original:

On Mon, Jun 8, 2009 at 3:05 AM, Rob<spamrefuse@yahoo.com> wrote:
>
>
> Hi,
>
> I'd like to verify whether I fully understand this part of the binary 
> density data:
>
> do ispden=1,nspden
>  write(unit) (rhor(ir),ir=1,cplex*ngfft(1)*ngfft(2)*ngfft(3))
> enddo
> For now I assume that cplex=1 for a GS calculation. Then
>
> 1. If spden = 1, I only have the total charge density in space.

Actually, you have the electron density, the charge density is minus
this. Also, what you really have depends on what formalism you are
using. If you used norm-conserving pseudopotentials (usepaw = 0) then
you have the pseudo-valence electron density. If you did a PAW
calculation (usepaw = 1) you have the pseudo-valence electron density
plus the compensation charge density. If you are trying to visualize
the electron density from a PAW calculation you should create the
density file with the pawprtden key word, not prtden. However, if you
want to chain this density into later calculations, you have to use
prtden.

>
> 2. If spden = 2, I have the total charge density in space for ispden = 1, 
> and
> the spin-up density in space for ispden = 2.
> Hence, if I want the spin-down density, I can find this by subtracting the 
> second
> data set from the first in each point in space, right?

Right.

> (By the way: what does "spin-up" mean here? Marjority? Minority spins?)

"up" means in the direction of the crystal z axis.

>
> 3. If spden = 4, I have again the total charge density in space for ispden 
> = 1,
> and the three x,y,z components of the magnetization for ispden = 2, 3, 4 
> respectively.
>
> ---
>
> Now, if cplex = 2?
> Then I have double as many data points.
> Is the charge density in each space point determined by the two numbers of a
> complex number?

Yes.

>
> Thanks,
> Rob.
>
>
>
>



-- 
Josef W. Zwanziger
Professor of Chemistry
Canada Research Chair in NMR Studies of Materials
Director, Nuclear Magnetic Resonance Research Resource (NMR-3)
Dalhousie University
Halifax, NS B3H 4J3 Canada
tel: +1 (902) 494-1960
fax: +1 (902) 494-1867
web: http://jwz.chem.dal.ca
jzwanzig@gmail.com, jzwanzig@dal.ca