[Ifeffit] Error in N (Number of Scatterers)

[Carolyn Carr]

Hello Mailing List,

I have read papers describing that EXAFS has an error regarding N the 
number of scatters of +/- 20%. The only original reference I can see to 
support this is "The effect of statistical noise on structural 
parameters in EXAFS data analysis" by L. Incoccia, S. Mobilio (1984, Il 
Nuovo Cimento D). However, in the more recent D. C. Koningsberger review 
"XAFS spectroscopy; fundamental principles and data analysis" (2000, 
Topics in Catalysis) he cites an error of 5% for N (although the paper 
cites slightly varying error for different absorber-scatterer pairs).

Several months ago, I wrote to the mailing list regarding the difference 
of fitting in R- and k-space in Artemis and received several responses 
revealing that some comments made in the Koningsberger review are no 
longer valid in Artemis. In my literature search, I did not find 
additional papers describing the error inherent in N when fitting in 
Artemis. Since the paper cited by Koningsberger (X-ray-absorption 
fine-structure standards: A comparison of experiment and theory, G. G. 
Li, F. Bridges, and C. H. Booth, Physical Review B, 1995) utilized Feff6 
for their theoretical standards and so does Artemis, is the error in N 
still the same? I was wondering if there is some literature that I have 
missed, or if the developers of the Demeter package can shed some light 
on this issue.

Thank You,

Carolyn Carr