Hi Dan,

At 12:27 PM 8/16/2004 -0700, you wrote:

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Should I add more paths?

I always feel more paths are better, until the fit stops working. They will reduce correlations and uncertainties in general, and also reduce the incidence of false minima. That does mean you'll have to include some multiple scattering once you get far enough out, but IMHO poorly constrained multiple scattering is better than none at all.

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Is there other parameters that I should add? Was it Ok to make 2 separate e0's?

This is an ongoing debate--it cropped up again on the Ifeffit list recently. I am not enamored of separate E0's without a very good reason, but others use them more freely. On the other hand, a separate ss for the nearest-neighbors from paths further out (I can't tell from your description if there's a significant separation between the three paths) is often called for. You might also consider fitting a third cumulant; the effect on a spectrum is not unlike fitting a separate E0.

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I think this is a pretty good fit, but I feel like there has to be something to improve it.

Seems not unreasonable, although it's hard to tell without uncertainties. That r-factor is a bit high for a three-path, five parameter fit, though.

--Scott Calvin Sarah Lawrence College