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. 

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