Re: [Ifeffit] R quality factor in k space

On Fri, Apr 17, 2009 at 8:08 AM, Cammelli Sebastiano wrote:

In the case of a linear combination fitting on the k space performed by ATHENA, the <∆chi> needs a correction. Is it correct to write:

R_factor ≡ < ∆chi(k space))> = √[ ∑ (chi_C(ki) – chi_E(ki))2 / ∑( chi_E(ki))2] ?

Where Chi_C(ki) = x1*chi1(k)+x2*chi2(k)  : chi1 and chi2 are the EXAFS functions of the two reference samples used for the linear combination procedure and x1, x2 (with 0

Yes, I that is correct. For fits in k-space, the chi data is often k-weighted, in which case all the 'chi' functions in these formulae should be the k-weighted chi(k). --Matt