I have an EPR spectrum (X-band) of a sample containing iron ions (we think that this is all Fe3+) in different environments. Using the Easyspin program, I try to simulate this spectrum to fit similar spectra.
The central wide signal with g = 2 is, judging by the literature [Kumar M.S. et al. DeNOxcatalysts: EPR and UV / VIS spectroscopic approach // J. Catal. 2004. Vol. 227, No. 2. P. 384–397.], magnetically interacting iron clusters. A signal with g approximately equal to 4.3 is non-interacting iron in octahedral distorted orientation [El-Malki E.-M., Van Santen R.A., Sachtler W.M.H. Introduction of Zn, Ga, and Fe into HZSM-5 Cavities by Sublimation: Identification of Acid Sites. 1999.].
As I understand the signal with g = 2, it can be simulated by specifying a large lwpp broadening for such a signal, but I do not really understand how to get asymmetric g = 4.3.
Dear Artem Minin!
Please write your question in more details to my E-mail [email protected]
I'll try to help you/
With best wishes
M.Kitai.
hi
the issue is with the baseline. you are assuming that zero marked on the data is the baseline which is not right. there is an additional contribution to the EPR spectra from your sample (is it a powder sample). Baseline need not be a linear function so that can shift the g = 4.3 signal up wrt the artificial baseline (zero).
just use the peak to peak as the linewidth to simulate. point is it appears to be asymmetric because of the background.
Hi Artem,
first you should give more info. You mentioned " I have an EPR spectrum (X-band) of a sample containing iron ions ". This info is not enough for answering this question while Fe EPR spectra strongly depends on the sample system. The spectra around 4.3 is probably due to large zero field splitting (due to crystal field). In simulation you should add spin-Hamiltonian term S.D.S. But, as I said, without knowing the sample specifically everything will be speculative. Further you may check our following paper which has similar Fe spectra as yours: Article Defect Structure and Materials “Hardening” in Fe2O3-Doped [B...
Thank you for your responses. The sample we are working with is a powder of xerogel derived from titanium isopropyl oxide and iron acetylacetonate.
Emre Erdem spectra in your work are very similar, but there is a similar structure described as a result of the interaction of an iron ion with a oxygen vacancy, but in our case vacancies are not very likely, our sample does not have a crystal lattice as such.
Ajay Sharma Do you think baseline distortion is the result of abnormal shooting conditions of the spectrum, or can this be a feature of the sample?
Krzysztof Tadyszak Thank you for your attention. The frequency was 9.870256 GHz.
