[Wien] Orientation Sensitive ELNES spectra

[Kevin Jorissen]

PS If anyone would be interested in building a little XCrysDen interface or
similar, where a user can click to rotate the crystal into the path of the
beam to set the orientation, that would be awesome.



On Tue, Apr 7, 2015 at 6:43 PM, Kevin Jorissen <kevinjorissenpdx at gmail.com>
wrote:

> 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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>>
>
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