[Pw_forum] Confused on nat definition

[Tone Kokalj]

On Thu, 2006-05-11 at 07:08 -0400, Luke Thulin wrote:
> Thank you for the clarification, it makes fine sense to me.  The
> original problem I am having is that I'm trying to input the titania
> antase structure.  It is fairly complicated, but I found a source,
> http://cst-www.nrl.navy.mil/lattice/struk/c5.html,  that spells it out
> clearly.  It says it's a body-centered tetragonal and lists six basis
> vectors, presumably to describe the peroidicity of the space group
> that it is in.  So I figured that ibrav = 7 for bct, nat = 6, and use
> the basis vectors to enter the atomic coordinates. Yet when I view my
> structure with XCrysDen, it looks nothing like anatase....

If you have the lattice basis vectors, you can choose ibrav=0 (means
custom lattice) and with CELL_PARAMETERS you input your basis vectors.
By doing that
you can use precisely the same "settings" as used by your source
mentioned above.

Regards, Tone