[Wien] A question about EELS

[Jorissen Kevin]

Hi BoKang,
 
 
TELNES2 calculates   
 
      integral(alfa,beta) [  dOmega      d^2/dE/dOmega  Sigma  (E,Omega==Q)  ]
 
which is indeed a differential cross section as a function of energy.  (alfa and beta are collection and convergence semiangles of microscope and detector ; E is energy loss, and Q=kf-ki is impulse transfer ; d^2/dE/dOmega  Sigma  (E,Omega==Q)  is the double differential scattering cross section).  This function is in case.elnes.  It is then broadened, and the result is written to case.broadspec.
 
Let us know if you have further questions!
 
 
Kevin.
 
 
 
 
Kevin Jorissen
University of Washington
Dept. of Physics
Box 351560
Seattle, WA-98195-1560
U.S.A.
 
phone +1 206 543 3904 
fax +1 206 685 0635 
e-mail kevin.jorissen at ua.ac.be 
web page http://fraangelico.phys.washington.edu/~jorissen

________________________________

From: wien-bounces at zeus.theochem.tuwien.ac.at on behalf of Shu Miao
Sent: Mon 4/16/2007 7:28
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] A question about EELS



The Y axis in emperimental spetra is intensity, i.e., the number of
signals per channel on the detector. In the featureless region, the
intensity in a spectrum is the atomic cross-section. However, in the area
with ionization peaks, the intensity is the atomic cross-section
multiplied by the number of holes in the final states in a transition
which is allowed by the selection rule. So I think it is more precise to
say the Y axis represents the probility, which is affected by a few
factors, of a scattering event with a specific energy loss.

Regards,
Shu Miao

On Mon, 16 Apr 2007, [gb2312] ²¨ ¿µ wrote:

> Dear wien users,
>
>         Recently, I used the telnes2 to calculate the electron energy loss spectrum of GaN, I think the column (y axis) of  the spectrum from  case.broadspec means differential cross section, but  recently , someone tell me the meaning of the column is intensity , I don't konw who is right? And is there any difference between intensity and differential cross section?
>
>       Any reply will be appreciated !
>
>                                                                            BoKang
>
>
> ---------------------------------
>  ÑÅ»¢Ãâ·ÑÓÊÏä-3.5GÈÝÁ¿£¬20M¸½¼þ


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