[xcrysden] Saving the grid for an expanded system

[Juan Jose Melendez Martinez]

Dear all

I have generated a supercell by expanding a single unit cell along each crystal axis; xcrysden behaves very nicely for this. I can also expand a 3D grid defined for the unit cell to the whole supercell, and then I can see the charge distribution within the latter, for instance. Once I got the grid (say the charge density) in the whole supercell, I saved it via the "Save Grid" command. And then I found a couple of issues:

1) The xsf file saved from the previous procedure contains the atoms in the supercell. However, when I load the file, I get the unit cell, not the supercell that I expected. 

2) I realized that the grid was saved for the unit cell only, not for the whole supercell. I can expand the grid again, but I cannot use it to compute charge differences, for instance. 

Did any of you experience something like this before? Any help, please?

Thanks very much in advance. 

Juanjo

Juan J. Meléndez 
Department of Physics 
University of Extremadura
Badajoz (Spain)