[Ifeffit] S02 and k_min

[Matt Newville]

Hi Mike,

On Sun, Dec 2, 2012 at 11:54 AM, Michael Morrill
<mike.morrill at gatech.edu> wrote:
> Hello everyone,
>
> I am currently performing a simple curve fit on bulk MoS2 using an atoms file for crystalline MoS2. I've found that increasing k_min on my fit (e.g. from 2 to 4) improves the quality of the fit (R-factor from 0.028 to 0.009), but also increases S02. If I use a large enough k_min (but not so large I run out of data), S02 gets as high as 1.2 +/- 0.05. This trend is observable for single and multiple k-weight fittings.
>
> While I understand that S02>1.0 does not necessarily invalidate the fit, I am not sure how to justify which parameter values are the best seeing that "0.8<S02<1.0" is often one of the justifications that everything "is reasonable." Ultimately, I want to assume the S02 is chemically transferrable and use it for curve fits on metal oxide supported MoS2.
>
> Any direction on the mater would be greatly appreciated.

I think you'll get more useful replies if you can provide a simple
project file that shows the effect.

--Matt