Hi Charles, I think that you understand correctly and that Athena doesn't label the axis correctly when multiple k-weights are being plotted. The FT are different when different k-weights are used because different regions of chi(k) are emphasized differently. Shelly -----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov on behalf of Charles Chusuei Sent: Mon 8/15/2005 12:23 PM To: 'XAFS Analysis using Ifeffit' Subject: [Ifeffit] Athena plotting multiple k-weights; confusion about "k" and "k-weight" Hello all: I'm confused about what is meant by "k-weight" and "k" and how they are used in the Athena plotting. As I understand it, "k" refers to the photo-electron wavenumber, k = [2m(E-E0)]/(h/2pi)^2]^ 0.5. A "k-weight" is the degree that chi(k) can be amplified. For instance k-weight of "2" in the Athena program plots a k^2*chi(k) versus k. A k-weight of "3" plots a k^3*chi(k) versus k, etc. However, in plotting multiple "spectra" using the same data file of different k-weighting one can see the different lineshapes for each k-weight [for instance assigning k-weights = 1,2 and 3]. Yet, the Athena output has the labels of "k^2*chi(k)" versus "k" even though there are multiple k-weights used. Is this a typo in the ordinate label where it would be more appropriately labeled as "k^n*chi(k)" versus "k" where n = weight, or am I fundamentally misunderstanding the relationship between "k" and "k-weight"? I'd appreciate assistance in understanding if the latter is the case. Thank you for your thoughts. Charles _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit