Re: [Ifeffit] Ifeffit Digest, Vol 171, Issue 14

Got it. Thanks for the response, Anatoly. Weizi On Fri, May 19, 2017 at 4:37 PM, wrote:

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Today's Topics:

1. Self absorption in CeO2 spectrum (Weizi Yuan)

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Message: 1 Date: Fri, 19 May 2017 16:37:54 -0500 From: Weizi Yuan To: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] Self absorption in CeO2 spectrum Message-ID: Content-Type: text/plain; charset="utf-8"

Dear all, I have measured some XANES spectra of CeO2 film(~220nm) in fluorescence mode at Ce L3 edge with two incident angles of 0.6 degree and 3 degree. My goal is to get relative surface sensitive (penetration depth~ 20 nm above edge) information of [Ce3+] from 0.6 o while bulk sensitive information at 3 o (penetration depth~ 160 nm above edge). In the meantime, I also collected CeO2 powder reference spectrum under transmission mode. The comparison is shown in the graph. The film at 3 degree has a sharper white line than the powder while at 0.6 degree, it is the opposite. I think this might be because at the surface of the film,it has more Ce3+ while when we detect the bulk it has more Ce4+. My question is how can I tell if I need self-absorption correction or not for the films in this case? Can I say I do not need self absorption correction because I have a higher normalized u for the film collected in the fluorescence mode than powder collected in the transmission mode? Thanks a lot for your comments. Weizi [image: Inline image 1]

-- Regards, Weizi Yuan, Graduate Student, Northwestern University, Ph:(+1)312-560-9619