[Ifeffit] Large Amplitude Values

[Scott Calvin]

Hi Gavin,

What are the uncertainties on the high S02 values?

Fluorescence is unlikely to be the culprit. While it can affect your  
ability to normalize properly, you're unlikely to account for a factor  
of 2 by normalization if the data is relatively decent. And self- 
absorption tends to suppress S02, not exaggerate it.

Why did you switch to fluorescence on just the handful of data sets?  
That might provide us a clue.

--Scott Calvin
Sarah Lawrence College

On Jul 30, 2010, at 10:47 PM, Gavin Garside wrote:

> Fellow X-Ray Absorption Enthusiasts,
>
> I have recently compiled a model that gives excellent visual fits in  
> R, q, and k space for bond spacing in a BCC structure.  This model  
> gives bond spacings that make sense, and are very close to what  
> would be expected from this set.  The R factors are very low, and  
> the enot values correspond quite well to the edge.  However, our  
> amplitude values are much larger than typically expected.  They come  
> in at the range of 1.8 up to 5.0, but only on a few data sets.  On  
> all the rest the amplitude values are 0.4 to 1.0.  Could this  
> increase in amplitude be attributed to the fact that we ran  
> florescence measurements instead of transmission, and have a weaker  
> signal coming to the detector?  What else could be causing this in  
> only one data set? All samples used in this model have the same  
> structure.  Thanks in advance to any replies, your help and time is  
> appreciated.
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20100731/617c6130/attachment.html>