[Ifeffit] boundary issue in artemis

[Scott Calvin]

Hi Marcus,

>From the graph, it looks likely that one of your sigma2’s is negative, causing the fit to blow up at high k. 

If so, then the apparently good fit below k=9 is actually a “false fit,” meaning that it looks good on a graph, but is nonphysical. Unfortunately, that means you have more work to do in adjusting the model; you shouldn't just narrow the fitting window and ignore the misfit.

Best,
Scott Calvin
Lehman College of the City University of New York

> On Jan 17, 2017, at 4:21 AM, mfehse <marcus.fehse at univ-montp2.fr> wrote:
> 
> Dear all,
> 
> im fitting Ti next neighbour environment and I'm facing the problem that above a k value of 9 the fit deviates completely and does not follow the data any more. I dont really understand what is happening, so im forced to limit my fitting window in order to avoid this effect.
> i have attached a plot in k space so you can better understand what im talking about.
> 
> any hints would be appreciated<Ti1st_disch_fit.png>_______________________________________________
> Ifeffit mailing list
> Ifeffit at millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit