[Ifeffit] Figure conversion - color to b/w

[Bruce Ravel]

On Monday 16 March 2009 01:22:01 pm Jenny Cai wrote:
> Thank you, Bruce and Scott. Actually, I  replotted all my figures using
> EXCEL except this one. It worked well for individual spectrum and linear
> combination fitting, but in least-squares peak fitting, I couldn't find the
> data for Gaussian and arctangent step peaks. Could you please let me know
> where I can find those data?  Thanks again.

Hi Jenny,

I have admitted many times on this mailing list that the peak fitting
dialog is one of the least polished parts of Athena.  There currently
is no way to get Athena to write out a file with columns for the
individual line shapes.  :( 

You can make a data group out of the fit and export that in the normal
manner.  For the individual line shapes, you have to reconstruct them
from the fitted values.

Here are the functional forms of the step functions used in Athena.
In each case, A is the amplitude term, E is the centroid term, W is
the width term, and e is the value on the energy axis:


  atan: f(e) = A * atan( (e - E)/W ) / pi + 0.5

  erfc: f(e) = A * erfc( (e - E)/W ) + 1.0

For the peak functions, Athena uses Ifeffit definitions as they are
given at http://cars9.uchicago.edu/~ifeffit/refman/node16.html

  gaussian: f(e) = A/(W * sqrt(2*pi)) * exp( -(e-E)^2 / 2*W^2 )

  lorentzian: f(E) = A*W / ( 2 * pi * ( (e-E)^2 + (W/2) ^2 ) )

All of these formulas are included in the little log file that gets
written out by the peak fitting dialog and are included there
specifically to help the user reconstruct the lineshapes in another
plotting program.

HTH,
B

-- 

 Bruce Ravel  ------------------------------------ bravel at bnl.gov

 National Institute of Standards and Technology
 Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2
 Building 535A
 Upton NY, 11973

 My homepage:    http://xafs.org/BruceRavel
 EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/