[Ifeffit] S02 selection from reviewer

Anatoly Frenkel anatoly.frenkel at stonybrook.edu
Sat Oct 2 10:46:40 CDT 2021

I think that the variability of S02 between different samples, detection
methods etc. may or may not be a big concern for you if 1) the error bars
in the CNs (that you are not reporting) are larger than the difference in
their mean values (that you are reporting), and/or 2) larger than the
difference between their mean values and the CN=6 that the reviewer is
asking about. If yes to either 1) or 2), then the variability in the S02
values for differently prepared samples may cause smaller variation in your
best fit values of CN than the error bars reported by your fitting program,
and your choice of fixing your S02 to be constant (0.85) may be justified.
You need to have a really bad non-uniformity or concentration problem so
that your effective S02 changed from the expected 0.85 (assuming it is what
a correctly performed measurement would give) to, say, 0.5 or 0.6 is my


On Sat, Oct 2, 2021 at 3:50 AM Peng Liu <liupeng5182 at gmail.com> wrote:

> Dear IFEFFIT members,
> I am sorry to bother you again. I asked about S02 selection for the first
> major revision. I just received the second revision. The reviewer is not
> satisfied with one S02 value for all our samples.
> "
> 1. I am still not satisfied with selected SO2 value (it is set to 0.85).
> SO2 is not transferable between different samples and detection methods. It
> is not possible to use a value obtained from different compound using
> transmission measurement mode to completely different other compound
> measured using fluorescence mode. One method to fix SO2 value is to measure
> diluted solution (to avoid self-absorption) of reference material in
> fluorescence mode. Other is to use multiple spectra fitting for all samples
> of interest (e.g. with Sb(V)) measured using fluorescence mode where SO2
> parameter is the same for all samples.
> At the same time I am confident that CN values 5.6, 7.1 and 6.9 correspond
> to CN(Sb-O)=6. I suggest reconsidering the SO2 value for measurements in
> fluorescence mode.
> "
> We do get the S02 from a similar reference material measured in
> transmission mode, and our samples were all measured in fluorescence mode.
> It is not possible to measure the diluted reference material in
> fluorescence mode in one or two months. If you could give me some
> suggestions, that would be great.
> --
> Best Regards,
> Peng Liu
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