[Ifeffit] What differences are there between Athena and AUTOBK backgrounds?

[Scott Calvin]

Hi all,

Today I tried making Athena perform exactly the same background 
subtraction as AUTOBK 2.61 (all parameters the same, working on the 
same data, using the same theoretical standard, etc.). I then let 
FEFFIT take the chi(k) data for each and perform a Fourier transform.

When I did this, AUTOBK would always generate a very low r (< 0.2 
angstroms) peak of significant amplitude that was nearly absent in 
the Athena background. There were other subtle differences as well, 
but that one stood out. Of course, a peak that low in r should have 
no effect on the fit, but it made me curious--were substantive 
changes in the background subtraction algorithm made when AUTOBK was 
incorporated into IFEFFIT?

--Scott Calvin
Sarah Lawrence College