[Pw_forum] charge density difference 1

[Hande Ustunel]

Hi,

I'm assuming you've read the file INPUT_PP under the Doc directory of your
espresso distribution. The meaning of the parameters are explained in
there. But to clarify, the &inputpp structure produces a file designated by
you contained in the filplot variable, so you can call this any name you
wish. The program will read the relevant quantity (say density) from your
outdir with your prefix, convert it into a format that is suitable for
further processing and write it into the file you have named in the
variable filplot. You should give separate names to all the densities you
want to take into account in the difference calculation. Once you have all
the density files, you should use filepp(n) to read in those files that you
have named previously with the correct weights. For instance if your system
is a surface+adsorbant, you may consider three different calculations with

    filplot = 'surface+ad'
    filplot = 'surface'
    filplot = 'ad'

Then when it's time to take the difference you could do

    filepp(1)='surface+ad'
    filepp(2)='surface'
    filepp(3)='ad'

with the obvious weights

    weight(1)=1
    weight(2)=-1
    weight(3)=-1

Make sure to be consistent in your naming scheme. 

Hope this helps,
Hande


On Tue, 3 Jun 2008, wangqj1 wrote:

>  
> Dear pwscf users
> I want to plot the charge density difference of ZnO on (1 1 0) surface ,but when I open the inputpp ,I meet some troubles.
> first, I don't understand the 'filplot',how to set it , I know it from the self-consistent,but in self-consistent which file is it ?
> second , I know that 'nfile' is the number of files will be dealed with ,but I don't know how to set the filepp(1)=? filepp(2)=? ...(nfile>1)
> Could somebody tell me how to set 'filplot'and filpp( ) ? It will be good if give me the example of charge density difference of ZnO on (1 1 0) surface .
> Everybody's advice will be appreciate .
> thanks
>  

-- 
Hande Ustunel
Department of Physics
Office 439
Middle East Technical University
Ankara 06531, Turkey
Tel : +90 312 210 3264
http://www.physics.metu.edu.tr/~hande