High-resolution nonresonant x-ray Raman scattering study on rare earth phosphate nanoparticles

Simo Huotari (1) , Edlira Suljoti (2, 3) , Christoph J. Sahle (1) , Stephanie Raedel (2) , Giulio Monaco (4) , Frank M. F. de Groot (3)

1 Helsingin yliopisto = Helsingfors universitet = University of Helsinki
2 HZB - Helmholtz-Zentrum Berlin für Materialien und Energie GmbH = Helmholtz Centre Berlin for Materials and Energy = Centre Helmholtz de Berlin pour les matériaux et l'énergie
3 Universiteit Utrecht / Utrecht University [Utrecht]
4 UNITN - Università degli Studi di Trento = University of Trento

We report high-resolution x-ray Raman scattering studies of high-order multipole spectra of rare earth 4d -> 4f excitations (the N-4,N-5 absorption edge) in nanoparticles of the phosphates LaPO4, CePO4, PrPO4, and NdPO4. We also present corresponding data for La 5p -> 5d excitations (the O-2,O-3 edge) in LaPO4. The results are compared with those from calculations by atomic multiplet theory and for the dipole contribution to the La 4d -> 4f transition from a calculation using time-dependent density functional theory (TDLDA). Agreement with the atomic multiplet calculations for the highorder multiplet spectra is remarkable in the case of the N-4,N-5 spectra. In contrast, we find that the shallow O-2,O-3 semicore excitations in LaPO4 manifest a relatively broad band and an apparent quenching of 5p spin-orbit splitting. The more sophisticated TDLDA, which has earlier been found to explain dipolar spectra well in Ba compounds, is less satisfactory here in the case of La

Mots clés: inelastic x-ray scattering; lanthanides; non-dipole; rare earths; x-ray Raman scattering

Domaines: Physique [physics]

Simo Huotari, Edlira Suljoti, Christoph J. Sahle, Stephanie Raedel, Giulio Monaco, et al.. High-resolution nonresonant x-ray Raman scattering study on rare earth phosphate nanoparticles. New Journal of Physics, 2015, 17, 10 p. ⟨10.1088/1367-2630/17/4/043041⟩. ⟨hal-01572913⟩