Dear Shaofeng,
On Wed, Aug 7, 2013 at 6:36 AM, Shaofeng Wang
Dear Bruce,
I am using Dathena to do some linear combination fitting. In your program, you give three methods for fitting, nomal, derivate and chi(k). I got three different results using these methods. My question is which one is better to obtain more reasonable result or what the purpose of each method is.
Yes, it is. The other ones are definitely worse. Now, slightly more seriously (yes, that was a joke), how different are the results? how different are fit ranges for these three fits? How good are the data and standards used over these ranges? As you might expect, a linear combination for chi(k) is generally intended for EXAFS, and so emphasizes distances of the nearest neighbors while "norm" and "derivative" is generally for the XANES portion of the spectra, and so emphasizes chemical state. Cheers, --Matt PS: Have you read the postings on this mailing list in the past couple months and weeks? Next time, please try to not exasperate Bruce (and the rest of us), and ask a question that can possibly be answered. Concrete examples and questions are much, much better than abstract questions. Please avoid asking "why is the blue curve always lower than the red curve"?