[Pw_forum] Supercells

[Ngoc Linh Nguyen]

Bertrand SITAMTZE wrote:
> Dear all,
>
> I wanted to built a supercell for my system in QE. I went through the 
> forum and saw some procedures. I followed this:
>
> 1. Upload the unit cell in XcrySDen, display the asymmetric unit, 
> modify the number of unit drawn to fit the shape of the desired 
> supercell (2*2*2) and then save the XSF file.
>
> 2. From the XSF file, the coordinates of atoms in the supercell are 
> obtained, in angstrom.
>
> But the problem is with the CELL. How should I built the CELL parameters
>
I think the CELL parameters should be calculated agree with lattice 
constants.

> and read the final structure with XCrySDen?
>
I don't understand "final structure".
>
> Note: I choosed the same ibrav as for the unit cell, then multiply the 
> celldm by 2, but the structure does'nt look fine in XCrySDen.
>
Why don't you post the input files that you have on forum, and everyone 
can help you fix it.

Best regards,

Linh
> Thans for your help
>
>
>
> *************************
> Bertrand SITAMTZE YOUMBI
> Laboratory of Material Sciences
> Department of Physics
> University of Yaounde I-Cameroon
> ************************************
>
>
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>
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 Nguyen Ngoc Linh, PhD Student
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