Hashem, it is not very clear, give mode details for each fitting scheme. Anatoly -----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov]On Behalf Of Hashem Stietiya Sent: Friday, January 16, 2009 12:13 PM To: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] difference between Zn-Zn/Fe and Zn-Fe paths Dear All, Is there a difference between fitting a second shell with two separate paths (Zn-Zn path and a Zn-Fe path) each with its own parameters and fitting that second shell with a combination of two paths (Zn-Zn/Fe)? When would I choose to do that latter, and how? I hope I made myself clear! Thanks, Hashem Stietiya Louisiana State University