Hi Anatoly,

Thanks for your quick response.

Yes, I actually asked the self absorption question about CeO2 a few weeks ago. And your answer that it is due to self absorption leads me to study more about it and I appreciate it.

In that last question, the strong attenuation of signal occurs in the incident angle = 0.6 o . However, when the incident angle is 3 o under room temperature ,air, the peak intensity is stronger than the CeO2 measured in transmission mode, which leads me to think that no over absorption correction needed here. And I try to conduct the correction which gives me crazily high (~9 after normalization) peak intensity.

This makes me further confirm that no strong self absorption effect here.

And if no strong self absorption in RT, air ,then why strong attenuation in RT, vacuum condition(case ii in my question)?

For your answer,I am a little confused. Are you saying self absorption occurred in only case ii or in both cases, even though the result of case i spectrum has a higher signal than the transmission mode data?

Thank you,

Weizi

On Thu, Jun 22, 2017 at 10:16 AM, <ifeffit-request@millenia.cars.aps.anl.gov> wrote:

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Today's Topics:

1. Self absorption or Ce4+ reduction in the CeO2 film? (Weizi Yuan)

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Message: 1
Date: Thu, 22 Jun 2017 10:11:05 -0500
From: Weizi Yuan <weiziyuan2015@u.northwestern.edu>
To: ifeffit@millenia.cars.aps.anl.gov
Subject: [Ifeffit] Self absorption or Ce4+ reduction in the CeO2 film?
Message-ID:
<CAKT5DaU1U2UX7bVUx9ffhvTfE7txqnZDgGu3cNujM6ceQyp6Hg@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Dear all,
I have measured some spectra of a CeO2 film(~200nm) grown on Yittria
stablized Zirconia(YSZ) substrate under 2 conditions.
(i) room temperature, ambient atmosphere
(ii) room temperature, vacuum (pO2~1E-6 atm) inside a graphite dome of the
DHS 1100 anton paar,
The spectra are collected in fluorescence mode. The incident angle is 3 o
and the fluorescence collection angle is 90 o.

My questions are:
(i) From the theory behind the FLUO program developed Dr. Daniel Haskel,
CeO2 spectra collected with a 3 o incident angle *would have a strong self
absorption effect and need*

correction , however, *the signal *is not attenuated compared with the
CeO2 powder taken in a transmission mode, shown in attached plot.
I've gone through many literature and people sometimes tell that whether
they have a successful self absorption correction by comparing the
spectrum with a spectrum taken under a transmission mode.
So I'm wondering if I can say that I don't need a self absorption
correction in this case?
(ii)
The Ce4+ peak in the spectrum collected under condition (ii) has a much
lower intensity. I think it is due to the reduction of Ce 4+ under vacuum,
however, the Ce3+ peak does not show an increased signal here. Which makes
ma doubt whether this is simply reduction of Ce *or might be from over
absorption? *

Thanks for any response.

[image: Inline image 1]
--
Regards,
Weizi Yuan,
Graduate Student,
Northwestern University,
Ph:(+1)312-560-9619
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End of Ifeffit Digest, Vol 172, Issue 15
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Regards,

Weizi Yuan,

Graduate Student,

Northwestern University,

Ph:(+1)312-560-9619