[QE-users] Format of FFT grid for Potential (Shivesh Sivakumar)

[Marcelo Albuquerque]

Hi Shivesh Sivakumar,

To understand how the grid is written in the file, you can check this page:
https://www.quantum-espresso.org/Doc/INPUT_PP.html#idm167

I hope it helps.


Bests.

*       Marcelo Albuquerque*

*          Ph.D Student*

*       Physics Institute*

*Universidade Federal Fluminense (UFF)*
*       Niterói/RJ - Brazil*



On Sat, Oct 10, 2020 at 7:01 AM Shivesh Sivakumar wrote:


> Hello users,
>
> I am trying to analyse the spatial variation of exchange-correlation
> potential 'V' for my system. I am doing this using the 'pp.x' module in the
> directory containing the charge density data for my system. I also used
> 'iflag=3' and 'output_format=5' which prints out a 3-D FFT grid which can
> be readily plotted.
>
>  I am trying to understand the format in which this FFT grid can be read.
> For instance, my FFT grid has dimensions 40x54x180. If I understand
> correctly, this means:
> 1) The lattice constant along 'a' is divided into 40 points, along 'b' is
> divided into 54 points and so on..
> 2) There are a total of 388800 (40*54*180) points printed, which correspond
> to the potential at each point , starting with varying 'x' first, then 'y'
> and then 'z'. Meaning,
> the first 40 points in the output should be (0,0,0), (0.025,0,0) ...
> (1,0,0).
>  The next 40 points should be                   (0,1,0), (0.025,1,0) ..
> (1,1,0).
>
>
> Am I right in this regard? Any help would be much appreciated.
>
> Thanks,
> Shivesh Sivakumar
> University of Washington-Seattle
> WA-98105
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> http://lists.quantum-espresso.org/pipermail/users/attachments/20201009/c04eb183/attachment-0001.html
> >
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> users mailing list
> users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
>
> ------------------------------
>
> End of users Digest, Vol 159, Issue 9
> *************************************
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20201010/533b9355/attachment.html>