Thank you so much! This is the first time I tried to use ifeffit mailing list. I would have never expected so many responses from so many scientists. I wish one day I could be able to contribute back to this great scientific community as well!
Thanks again! Mengling On Thu, Sep 29, 2011 at 8:00 PM, Matt Newville <newvi...@cars.uchicago.edu>wrote: > Hi Mengling, > > 2011/9/29 Mengling Yi Stuckman <stuckman...@osu.edu>: > > Thanks for all the response! They are all very helpful! > > Just want to make sure that I get the information right and a few > follow-up > > questions: > > 1. I'd better contact the beamline engineer to ask for the sensitivity > for > > Tl. > > Yes! > > > 2. Fe fluorescence interference could be decreased by adding a few layer > of > > Al foil. I knew that I did that when I measured As fluorescence. So this > is > > ok. > > Yes. > > > 3. Pb fluorescence interference is very hard to eliminate. Therefore, > EXAFS > > for Tl is very hard to get. Actually, I didn't see any papers on Tl EXAFS > > and maybe that is why. The research question I want to answer is: > > what structure Tl is bond to in the fly ash? Tl(I) and Tl(III) could > > theoretically bind to sulfate, nitrate, bicarbonate, etc.. I saw some > papers > > that are using nitrate, sulfate, bicarbonate Tl salt as references for > > micro-XANES measurement. And then they compared the XANES in the end. Is > > that a better approach than EXAFS to answer the question? > > Well, maybe not "better", but generally tolerant of less good data. And > also generally more "directly sensitive" to oxidation state and ligand. I > won't kid you though - Hg, Tl, and Pb L3 XANES can be tricky to analyze > well, as the features are not very well resolved. > > > 4. To increase the intensity, we can condense the ash by pressing it into > > pellet. The fly ash from coal combustion power plants are already pretty > > compacted. They are mainly gypsum in most cases. I dont' know if that > helps > > or not. > > It won't hurt. > > > 5. This is the first time I heard about non-energy dispersive detector, > e.g. > > PIPS diode. We are planning to use 13-element detector. What is the > > advantage of using one way or the other? If I do want to concentrate on > > XANES, would be helpful to ask the beamline engineer for the possibility > of > > changing detectors? > > I'd start with the 13-element Ge detector and see how that goes.... > > Cheers, > > --Matt > > _______________________________________________ > Ifeffit mailing list > Ifeffit@millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > -- Mengling Yi Stuckman Graduate Research Assistant Civil and Environmental Engineering and Geodetic Science Ohio State University 2070 Neil Ave., Columbus, OH, 43210
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