[Pw_forum] How to plot the 2D-charge density for a triclinic or monoclinic box

[Hongsheng Zhao]

On Sunday, September 14, 2008 at 18:02, tone.kokalj at ijs.si wrote:
> On Sun, 2008-09-14 at 11:50 +0800, Hongsheng Zhao wrote:
>> In the above case, we can *scale* from the e1 and e2 to obtain the the corresponding two
>> span vectors easily, but for the 2D charge density using by xcrysden,
>> how can I *scale* from those obtained by e1 and e2 to suit the
>> xcrysden's needs within the plane decided by the two span vectors?

> OK, I see your point. These are two distinct issues.

> (i) you can calculate 2D plane using the pp.x program. This requires the
> orthogonal spanning vectors + origin. (my yesterday emails referred to
> this). When you manually calculate the two orthogonal vectors, then you
> need to choose the origin + the size of the two vectors (the "scaling"
> referred to that).

> (ii) you may calculate the whole 3D unit cell by pp.x, and then xcrysden
> can plot the three basal planes out of it (ab,ac,bc), and here
> ortogonality doesn't metter. With xcrysden, all you can do further is to
> "clone" these planes with periodic images so as to obtain plot on a
> larger area (use "Expand" tab for this).

Due to the pp.x program require that all of the three span vectors
must be orthogonal to each other, so this will induce the 3D unit cell
by pp.x with the three span vectors determined by Gram¨CSchmidt process
not always can be expands to the corresponding crystallographic cell.
I mean, the "Expand" tab of xcrysden will not always give the
corresponding three basal crystallographic cell planes by using the the abobe three span
vectors given by Gram¨CSchmidt process.  Am I right?

Sincerely yours,
-- 
Hongsheng Zhao <zhaohscas at yahoo.com.cn> 
Xinjiang Technical Institute of Physics and Chemistry
Chinese Academy of Sciences 
GnuPG DSA: 0xD108493
2008-9-14