[Wien] Orientation Sensitive ELNES spectra

[Kevin Jorissen]

Thanks, Gavin: 1/ yes, and 2/ yes.  I admit that the Euler angle approach
gets confusing in a very general crystal, but for most simpler structures
e.g. hexagonal systems like graphite, using just the beta angle (second
angle) is all you need.

Cheers,

Kevin


On Mon, Apr 6, 2015 at 1:30 PM, Gavin Abo <gsabo at crimson.ua.edu> wrote:

>  1) You might want to see K. Jorissen's PhD thesis [
> http://www.wien2k.at/reg_user/textbooks/thesis_jorissen_telnes.pdf ].  It
> looks like he developed Telnes while studying graphene sheets, where the
> c-axis was the z-axis. So the beam goes along the z-axis [
> https://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg00306.html
> ].
>
> 2) I think the rotation matrices used for the Orientation Sensitive are
> likely those given in SRC_telnes3/rotation.f.  It looks like the rotation
> matrices are those of the zyz convention for the Euler angles [
> http://www.ccp14.ac.uk/ccp/web-mirrors/klaus_eichele_software/klaus/nmr/conventions/euler/euler.html
> ].  If you set g2 (i.e., beta) as 90 degrees, it looks like the beam will
> be incident on the xy-plane of the sample.
>
> On 4/6/2015 12:08 AM, Hajar Nejati wrote:
>
>  Dear Wien2k users
>
> I am interested in calculating the ELNES spectrum for a crystal and I am
> faced with the following problems:
>
> *1)* For an "Orientation Sensitive" calculation, the Euler angles (alpha,
> beta, gamma) are required.
> The crystal structure is described with respect to an Oxyz system. However
> it is not clear to me what this relative orientation corresponds to when
> for example the input (alpha, beta, gamma)=(0,0,0) is used. How is the
> option (0,0,0) corresponded to the electron-beam parallel to the c-axis?
>
> *2) *What should be the input for (alpha, beta, gamma) in order to have
> the electron beam along the x-axis or y-axis or particularly in the
> xy-plane?
>
> I searched the mailing list but I could not found a clear response.
>
>  All the best.
>
>  Hajar
>
>
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