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Dear all:

can any of you send me the 64-atom super cell of mgo crystal POSCAR file for VASP simulation? I really do not want to install software to prepare just one crystal structure for vasp. Thank you very much.

If you are referring to a rocksalt structure of MgO, you should really look in your introductory condensed matter physics book. To set up lattice vectors and positions for this structure is very straightforward and you don't need any software for structure preparations.
<span class='smallblacktext'>[ Edited Tue Apr 05 2011, 05:44PM ]</span>

Hey Dan,

I would be interested in knowing how you can generate POSCARS without a software, can you pls give us like 5 mins of your time to explain how you can do this once and for all!!

Cheers,
Alexandra

MgO
1
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Mg O
32 32
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@lexa Why would you require specific software for structure generation for simple geometries? Ok, sure for supercells with many primitive cells it may be easier for you, but you really should be able to write down the positions directly by yourself since it is very straightforward. Especially for the simple rocksalt structure. If you are dealing with more complex structures such as multiple orientation relationships of grain boundaries between multicomponent materials, then a generation software would be indeed b helpful. But again it is no requirement.

Cheers,
/Dan

This is easy, you just have to think about it. First, take the .cif file containing the primitive cell positions and translational vectors. Then apply a translational matrix to those positions to generate new positions. You can use any programming language you wish to do this. You could even do it in open office or MS Excell.

@lexa, could you tell me how you generated the supercell? I have a rather complex crystal structure and I would like to know if an user friendly software exists for this purpose. Thanks in advance...

Dear SSI,
for generating supercell google may be helpfull:
https://wiki.fysik.dtu.dk/ase/ase/lattice.html
http://www.cmmp.ucl.ac.uk/~lev/codes/lev00/
http://tfy.tkk.fi/~job/vasputil/
http://www.lpmd.cl/
http://www.wxdragon.de/
...and many more.

Also, check this website for POSCAR files for thousands of structures:

http://materialsproject.org/