[Ifeffit] quotation of figures

[Scott Calvin]

Whoops--it helps if I actually read the formula that the person  
actually wrote.

--Scott Calvin
Sarah Lawrence College

On Jul 16, 2008, at 3:40 PM, Bruce Ravel wrote:

> On Wednesday 16 July 2008 15:27:27 Scott Calvin wrote:
>> Bruce--I'm not following your critique of the third panel. Where's  
>> the
>> confusion? I see the disorder term, and I see the mean-free path  
>> term,
>> but I don't see them inappropriately labeled or confused with each
>> other (aside from the common use of "Debye-Waller factor"). Unless
>> perhaps it's just that the spacing and arrows in the label "From ab-
>> initio calculations or from reference compounds"  is confusing? (i.e.
>> it kind of looks at first like the slide claims that the mean-free
>> path comes from a reference compound)
>
> Unless you redefine sigma^2 such that it has units of 1/angstrom^2 and
> it subsumes the 2 we usually put in that exponential, the expression
>
>    exp( -k^2 / sigma^2 )
>
> is incorrect.  I concur that one is always free to define ones terms.
> But redefining what sigma means in the exafs equation can only lead to
> confusion.
>
> (BTW, When you analyze your data by comparison to an empirical
> standard, I would presume that the mean free path is considered to be
> chemically transferable.)
>
> B
>
>