[Ifeffit] Stoichiometry from EXAFS data

[Peter Zalden]

Dear Feff users,

lately, we measured a sample containing Sb and Te at EXAFS beamline 
CEMO, Hasylab and are wondering whether one can determine the 
stoichiometry from the height of the different K edges´ steps, if one 
normalizes the values on the edge steps of the elements (cf. 
http://physics.nist.gov/PhysRefData/XrayMassCoef/tab3.html). The 
absorption gases and the specimen were not changed for the different K 
edges.
Of course, I have already tried doing so and from statistical 
reproducibility and from the resulting values compared to the expected 
ones I would estimate an error of this method of about 1%. A source of 
error that I could imagine originates from the different beam position 
at different energies combined with a slight inhomogenity in the pressed 
sample powder. Now my question is: Are there any other sources of error 
that I should take into accout? Is there any reference on this method 
from a more experienced user that I could cite?

Kind regards,
Peter
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Dipl.-Phys. Peter Zalden
I. Physikalisches Institut IA, RWTH Aachen, 52056 Aachen
EMAIL: zalden at physik.rwth-aachen.de