[Ifeffit] weights data processing

[Stefano Ciurli]

Hi folks,

1) when removing background using athena, there is an option of using 
a k-weight different than 1 (I am NOT talking about k-weight for FT). 
I noticed that changing this parameter the resulting chi(k) does not 
change significantly. Actually, going from 1 to 4 as a value for 
k-weight for Bkgd removal, the only effect I see is a significant 
reduction of the peak below the first coordination shell in chi(R) 
while the other features of the spectrum are essentially the same in 
terms of absolute and relative intensity. A drastic change in both 
chi(k) and chi(R) is seen if I use k-weight = 5 and above. What is 
the exact meaning of it? I know what the meaning is in the FT 
process, but I do not see the reason why I should use a weight 
different than 1 (let's say 3 for my noisy data) for background 
removal. How should I behave? SHould I take the largest value of 
k-weight so that the essential features of the chi(k) and chi(R) do 
not change?

2) In artemis, is it a bug or a wanted feature to have the 
possibility to activate more than one button for k-weight for the fit 
and FT? I suppose it is a wanted feature, but then I wonder what is 
the meaning of using more than one weight for the fit and FT. I am 
sure some of you can unveil this enigma.

Ciao,
Stefano
-- 
____________________________________________

Stefano Ciurli
Professor of Chemistry
Department of Agro-Environmental Science and Technology
University of Bologna
Viale Giuseppe Fanin, 40
I-40127 Bologna
Italy
Phone:	+39-051-209-6204
Fax: 	+39-051-209-6203

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