xraypy / xraylarch

Larch: Applications and Python Library for Data Analysis of X-ray Absorption Spectroscopy (XAS, XANES, XAFS, EXAFS), X-ray Fluorescence (XRF) Spectroscopy and Imaging, and more.
https://xraypy.github.io/xraylarch
MIT License
138 stars 68 forks source link

Formula question in larch.xafs.preedge #537

Open YundaoJing opened 1 week ago

YundaoJing commented 1 week ago
2  post-edge: a polynomial of order nnorm is fit to mu(energy)*energy**nvict
   between energy=[e0+norm1, e0+norm2]. nnorm, norm1, norm2 default to None,
   which will set:
     nnorm = 2 in norm2-norm1>300, 1 if norm2-norm1>30, or 0 if less.
     norm2 = max energy - e0, rounded to 5 eV
     norm1 = roughly min(150, norm2/3.0), rounded to 5 eV

The post-edge formula should be 'mu(energy)*energy**nnorm', am I right?