[xcrysden] Fermi surface for FCO

[Tone Kokalj]

On Mon, 2005-06-20 at 06:45 -0700, Eyvaz Isaev wrote:
> Dear Tone,
> 
> Now I try to plot the FS for a face centered
> orthorhombic   (FCO) structure. Unexpectedly, on
> screen I have got HCP structure. I mean  getting basis
> vectors for FCO lattice  XCrysDen plots Brillouin zone
> for HCP. 
> As fas as I remember it should be a little bit
> different and depends on the c/a ratio.

I would be very much surprised that xcrysden did a wrong job here.
Namely, the algorithm for the Brillouin-zone (BZ) construction is
general (it does not know about the lattice-types). It merely takes the
primitive reciprocal lattice vectors (whatever they are) and generates
the BZ.

I am not familiar with the FCO lattice type (hence this is possibly
stupid(wrong) argument): the convetional FCO cell has orthogonal lattice
vectors, but the corresponding primitive vectors are not orthogonal.
Maybe your b/a and c/a ratios are such that the primitve lattice vectors
are close to those of HCP. Can you check this point. If you really
thinks there is a bug, please send me this particular example.

Regards, Tone