[Ifeffit] Inconsistency of the amplitude reduction factor

Bruce Ravel bravel at bnl.gov
Thu Sep 18 08:11:03 CDT 2014

On 09/18/2014 08:20 AM, HOON Kim wrote:
> I'd like to be more specific about my obtained results,
> At reference state (that means without any applied current), the
> amplitude reduction factor was 0.77
> At 20% charge, it was 0.67
> 40% charge = 0.66
> 60% charge = 0.63
> 80% charge = 0.68
> full charge = 0.67

My other comment on this thread is that you are not being specific 
enough.  Without error bars, it is not possible to interpret those 
numbers in any physically meaningful way.  Similarly, without knowing 
the uncertainty, it is hard for us to comment substantively on your 

I would imagine that, given the likely size of your error bars, 0.63 and 
0.68 are not different results.  In fact, it is possible that 0.63 and 
0.77 are not different in any defensible way.  That may be yet more 
likely given the possibility of systematic error due to changes in 
morphology -- which would not be properly captured in the statistical 
error bars --  as I mentioned in my last post.

Remember: ALWAYS cite error bars with numbers from a fit!


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

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

  Homepage:    http://bruceravel.github.io/home/
  Software:    https://github.com/bruceravel
  Demeter:     http://bruceravel.github.io/demeter/

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