Re: [Ifeffit] Applicable scope of delr=alpha*reff

Yeah, thanks bruce and Scott. It's been a long time since I've looked at and done synchrotron science, and today just decided what the heck, let's read some of what's going on in the Ifeffit mailing list. Just a friendly stop by from a guy that spent a lot of time in college during the summers trying to figure this stuff out, and noticing strange how after several years, I actually understand the information provided by Bruce and Scott much better now than I did when I was actually doing this kind of research. Happy researching to all. -- Jasen Vita, Sarah Lawrence Alum On Wed, Aug 3, 2016 at 5:19 AM, woschangqiang wrote:

Than you very much for the provided link from Bruce Ravel and answer from Scott Calvin.

At 2016-08-02 20:58:36, "Scott Calvin" wrote:

If you think it’s plausible that the crystal is expanded or contracted isotropically and homogeneously, then it’s a model worth trying. It’s usually my first model for fitting just about any crystalline material. Often, the resulting fits are not good, and then I have to try other models. But sometimes, particularly when the differences from my model structure are small, it works fairly well.

In terms of the criteria I described here https://www-ssrl.slac.stanford.edu/conferences/workshops/srxas2011/presentat... and elsewhere, it has the advantage of “simplicity” under criterion 4. Whether or not it produces a good fit under the other criteria is, of course, something that you have to find out for each system.

—Scott Calvin Sarah Lawrence College

On Aug 2, 2016, at 6:27 AM, woschangqiang wrote:

Hi, everyone. delr=alpha*reff is very powerful in the fit of cubic system. And I want to know whether this function can be used in other crystal system. Thank for your patient answer.

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