[Ifeffit] Information content from Athena for Hamilton test?

[Wayne Lukens]

HI Will,

I am not entirely sure how this value is determined in Athena, but the
number of independent data in a XANES fit is the data range divided by the
resolution. If you have a spectrum with a strong pre-edge peak, you can
determine the resolution from its width. Otherwise, the resolution is a
convolution of the core-hole broadening and the beamline energy resolution.

Athena gives a value that is very close to the value determined directly
from the width of a preedge peak.

Sincerely,

Wayne

On Sun, Apr 9, 2017 at 8:59 PM, Will Bennett <w.bennett at griffith.edu.au>
wrote:

> Hi everyone,
>
> Just a quick question regarding the "Information Content" output in
> Athena's LCF window. I've recently been playing around with using the
> Hamilton test (as outlined in Scott Calvin's book "XAFS for Everyone") to
> interrogate my combinatorics results. As many of you will know, this
> requires an estimate of the number of independent measurements in the data,
> in order to determine the degrees of freedom and subsequently the "a" value
> for computing the Lower Incomplete Beta Function. Would Athena's value for
> "Information Content" be appropriate to use as an estimate of the number of
> independent measurements in this case? How is this value of "Information
> Content" determined in Athena?
>
> Thanks in advance.
>
> Will
>
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-- 
Wayne Lukens
Staff Scientist
Lawrence Berkeley National Lab
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