[Ifeffit] High SO2 value

Scott Calvin SCalvin at slc.edu
Thu Apr 9 09:03:34 CDT 2009

Hi Abhijeet,

There is no reason to fit the S02 separately for all shells. You  
should use the same S02 parameter for all shells.

Ifeffit's job is to adjust the squiggly curve that comes out of the  
model until it looks like the squiggly curve that comes from the data.  
That's it. It doesn't know any physics or chemistry. So it's quite  
capable of doing nonsensical things in order to make the curves  
similar. Your job is to inject sense into the process, by using  
reasonable constraints.


On Apr 9, 2009, at 3:42 AM, abhijeet gaur wrote:

> Hi all,
>          I am fitting a copper foil.  I fit the first shell by using  
> first ss path and got it fitted nicely. Then keeping the parameters  
> for the first shell to be fixed , I tried to fit the second shell by  
> taking first and second ss but it is always coming a littel  
> displaced and not fitting well also. But when I added the the third  
> ms path to it , the fit becomes very nice. But the problem is that  
> parameters for third path are coming very bad. And one more problem  
> is that the value of SO2 for second shell is coming very high around  
> 1.5. I am not able to understand the results.
> Thanks in advance
>                               Abhijeet Gaur
> _

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