[Pw_forum] Crystallographic question.

[sir_puding at tut.by]

> Hi,
> One way would be use the Brillouin zone of the 8-atoms cell for both
> cases. This is straightforward, but it may be not very pretty. The
>  8-atomos Brilloiun cell has the same information as the 2 atoms cell, it has 1/4 of
> the volume, and 4 times the number of bands.

Thanks, Eduardo. Your suggestions were very helpful.
I think I've found the answer. I have plotted the BZs for SP and FCC real lattices
with the same lattice constant and took the difference.
If we "sum up" first and second BZs for FCC lattice we get the SC
lattice BZ. So in the case of perfect Diamond, SC lattice with 8 atom
basis contains twice more k-points than in FCC 2 atoms case. But the
half of them are the same as for FCC lattice first BZ.

THNX.


Sergey.