[Wien] Possible technical error in telnes

[Peter Blaha]

I'm not running elnes very often, and I also do not really understand 
your problem/ or what is not honored. As far as I understand:

In the input you enter an energy range from zero (=EF) to something.
This means all spectra (of different O-atoms) start at zero and possible 
shifts should be evident.
You also enter an edge onset, which could be taken as the corresponding 
core eigenvalue-EF (although this is a very bad estimate of the core 
binding energy - and excitonic effects will change this also.

The shift (relative positions) of 2 O-atoms in the same compound could 
come from:

1)different position of O-p states in the conduction band

2)different core BE

2)different excitonic effect.

1) is trivial and should come out of the simulations

2+3 are much more difficult to estimate. The groundstate core-energies 
will most likely not give proper corelevel shifts and no excitons.

You can do several core hole calculations, which for an insulator are 
usually mandatory anyway. The core energies of such calculations are too 
low (that would require more half a core-hole), but excitonic effects 
might be covered partially.




On 10/19/18 3:10 PM, Laurence Marks wrote:
>  From what I can see, it appears that telnes3 is ignoring the absolute 
> energy range that the user inputs. In a case I just ran to look at an O 
> K edge it did not matter whether I used 500-530 as the energy range or 
> 520-550, in both cases the EELS zero was the same and the spectra looked 
> identical. [1]
> 
> Of course the absolute edge position is dodgy. However, I am interested 
> in relative shifts for different atoms in a single structure. I will 
> argue that at a minimum the core energy should be reported in the 
> spectrum output file. (I will probably hack my version to do this.)
> 
> [1] My energy range got cut to 10 eV as I did not go high enough in 
> lapw1, but this should not matter.
> 
> -- 
> Professor Laurence Marks
> "Research is to see what everybody else has seen, and to think what 
> nobody else has thought", Albert Szent-Gyorgi
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-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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