Recently, I recorded Copper foil EXAFS as a reference in (Dispersive EXAFS) transmission mode at Soleil, Paris. For understanding the data quality (of my sample), i started fitting copper EXAFS through Artemis. After the DATA extraction, i fitted copper in Artemis and found a shift in energy. For this reason, i have modeled with and without corrected Copper EXAFS in Artemis. Initially, i started with first shell and progressed to three shell fit through step by step. During the course of fitting, some of the following troubles have been faced. Please help me to rectify it.

For first shell fit: Everything goes well and converged to reasonable physical values of copper foil. Whereas for further increment in copper shells leads to increase in Debye-waller factor for all three shells and increase in uncertainty value of E0 than the actual value.

Moreover, i have noticed that the (increase of shells in the fit) not only changes the physical parameters and also modifies the Fourier transform.  The inference are the following: A shift in first and third shell of Cu-Cu are observed, respectively, to larger and shorter distance than the experimental spectrum with diminished second shell amplitude.

Although Copper foil EXAFS is standard and well known sample, i am stuck with fitting. Please help me to overcome these problems. For your reference, project file of Copper file is attached with this email.

Regards.

Raj