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Description
Lanthanides have nowadays become of vital importance in advanced materials and technology. Applications in laser science, solar cells, fluorescent lamps and a new organic light-emitting di-odes components, as well as luminescent probes are strongly related with their optical and/or elec-tronic properties.
Samarium and its compounds are among the most frequently used lanthanides in the investiga-tions during the last years. But the precise excitation property, especially the plasmon structure of samarium is still not known. It is not surprising because all lanthanides are highly reactive ele-ments and interact strongly with oxygen and hydrogen. So, experimentally it is really a challeng-ing to obtain accurate results.
Da et al. [1] developed a reverse Monte Carlo (RMC) method for the derivation of the energy loss function (ELF) and thereby the dielectric function and optical constants of solids in a much wider photon energy range than that of the usual optical measurements.
Our RMC technique was used to obtain the electron energy loss features buried in the REELS spectra of samarium [2]. The accuracy of the ELF was checked by applying sum rules. We found that the ps- and f-sum rules fulfils very accurately and reach the nominal values with 0.2% and 2.5% accuracy, respectively. We were able to separate the contribution from the bulk and the surface excitations. We show the detailed excitation characteristic in the optical data in the energy range between 3 and 60 eV.
This work was supported by Fund for Bilateral Relationships Between China and Hungary in Sci-ence and Technology (S&T) (2021-1.2.4-TÉT-2021-00055).
References
[1] B. Da B et.al., Journal of Applied Physics, 113, 214303 (2013)
[2] T.F. Yang et.al., Scientific Reports 13:3909 (2023)
