[Wien] TELNES and Euler angles

[Dimitris Kechrakos]

Dear Wien2k users

I am interested in calculating the ELNES spectrum for a crystal and I am 
faced with the following problems :

Problem-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.
What should be the input for (alpha, beta, gamma) in order to have the 
e-beam along the x-axis or y-axis or along
an arbitrary direction (theta,phi) ? I understand that the question is 
related to the definition of Euler angles adopted
in the code.
In the UG (pg.129) it is said that "This key ...to use the particular 
sample-to-beam orientation defined by the 3 Euler angles."
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.

Problem-2
I followed the steps :
- recompiled lapw2 setting LXDOS=3 in modules.F (as suggested)
- Initialization (using ISPLIT=4 in the case.struct file).
- ran SCF
- changed to ISPLIT=99 in case.struct.
- edited case.innes (using w2web)
- x lapw2 -qtl -c (using w2web) => got the following error message


    ----------------------- error message --------------------


    Modified lapw2 -qtl for TELNES.2

calculation is orientation sensitive -> we need ISPLIT=99

    * backing up AB.struct
    * set ISPLIT=99 for atom 2
      *Error* - incorrect space group symbol
      *Error* - incorrect space group symbol
    * write modified AB.struct
    * *command:* x lapw2 -qtl -c

      *output*:

      x lapw2 -qtl -c   
      Abort
      7.768u 0.556s 0:02.35 353.6%	0+0k 0+0io 0pf+0w
      error: command   /home/dimitris/Programs/wien2k/8.2/lapw2c lapw2.def   failed

    * restore AB.struct


    -----------------end of  error message --------------------

Then turned to the console and gave exactly the same command (x lapw2 
-qtl -c)
and everything proceeded fine (empty lapw2.error file).
Continued with w2web and got the spectrum eventually.
Is it clear to anyone why this is happening ?

DK



-- 
----------------------------------------------------------

Dr Dimitris Kechrakos
Institute of Materials Science
National Center of Scientific Research "Demokritos"
153 10 - Agia Paraskevi
Athens, GR
tel: +30-210-650 3335
fax: +30-210-653 3872
email: dkehrakos at ims.demokritos.gr, physengin at gmail.com
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