Hi all,
Corwin Booth (at LBL lab, Berkeley) presented a very nice procedure for making these corrections for EXAFS at the conference, improving the work of L. Troger, et al from the mid 1990's.
I'd be interested in hearing others opinions on this topic, and whether this should be included in Ifeffit.
Corwin Booths approach to selfabsorption correction seems to be very nice. I think that especially its possibility to give up the "infinite sample thickness" limitation could be an important improvement over the previous approaches. Still, it makes two (more or less implicit) assumptions: * the detector surface has to be parallel to the x-ray beam (phi + theta = 90 deg) * the detector has to have a neglectable solid angle
I'm not sure if these two assumptions hold for most fluorescence experiments? surely no ! (cf ID21 at ESRF) and most future expeirments won't be that "ideal" for sure.
When I collected my last fluorescence data a couple of years ago, large solid angle detectors (like Lytle-detectors) were still in use. I have shown that Troegers approach to selfabsorption correction can be generalized for large detector surfaces (Phys. Rev. B 60, 9335 (1999)). In principle this should be also possible for Corwin Booths formula.
except for cations above than Zr.
But when integrating over large solid angles, the exact geometry of the experimental setup plays a crucial role in determining the selfabsorption correction and I doubt that a useful implementation into iFeffit would be possible.
yes but if you say so nothing will ever work. one has to start. I would be amazed to see that one day, the perfect self absorption correction code will work.
If, however, everyone is using solid state detectors now, I would say that implementing Corwin Booths code into iFeffit could be worth the effort.
the most important to me is to expand it to XANES (as in FLUO by Haskel) where self-absorption effects are relatively more important as compared to the EXAFS, and going opposite ways depending if you considering the pre-edge or the main edge regions (because of the collapsing mu0 near E0). FF -- Francois FARGES Laboratoire des Géomatériaux Université de Marne la Vallée 5 Bd Descartes-Champs S/Marne 77454 Marne la Vallée cedex 2 TEL: 01 49 32 90 57 from outside France: +33 1 49 32 90 57 FAX: 01 49 32 91 37 from outside France: +33 1 49 32 91 37