Evidence of Mixed-Valence Hydrated Europium-Chloride Phase in Vacuum by Means of Optical and Electronic Spectroscopies

Mathieu G Silly (1) , Stéphanie Blanchandin (1) , Fausto Sirotti (1) , François Lux (2, 3) , Sylviane Chevreux (4) , Gilles Lemercier (4) , Fabrice Charra (5)

1 SSOLEIL - Synchrotron SOLEIL
2 LPCML - Laboratoire de Physico-Chimie des Matériaux Luminescents
3 ILM - Institut Lumière Matière [Villeurbanne]
4 ICMR - Institut de Chimie Moléculaire de Reims - UMR 7312
5 LEPO - Laboratoire d'Electronique et nanoPhotonique Organique

Studying the optical and electronic properties of commercial hydrated EuCl 3 salts, we took advantage of the manifestation of the unfilled 4f valence shell in photo-luminescence and core-level photoemission spectroscopies to unambiguously identify contributions from both Eu 3+ and Eu 2+ configurations. Lanthanide ion salt exhibits sharp spectral lines in good agreement with Eu 3+ oxidized state. Surprisingly, the photoemission spectrum of europium 4d core level presents a singular asymmetric shape component attributed to Eu 2+ species, thus revealing a significant amount of divalent europium. X-ray absorption spectroscopy confirmed the presence of Eu 2+ species in proportions that depend on the origin of the salt and on the applied material processing.

Domains: Physics [physics]

Mathieu G Silly, Stéphanie Blanchandin, Fausto Sirotti, François Lux, Sylviane Chevreux, et al.. Evidence of Mixed-Valence Hydrated Europium-Chloride Phase in Vacuum by Means of Optical and Electronic Spectroscopies. Journal of Physical Chemistry C, 2013, 117, pp.9766 - 9771. ⟨10.1021/jp312500f⟩. ⟨cea-01478836⟩