Multiplet and lifetime effects in the4dphotoelectron spectrum of Eu

Abstract

A high-resolution 4d photoelectron spectrum of Eu has been measured. The spectrum reveals a rich structure reflecting multiplet splitting due to 4d-4 f , 4f-4 f , and spin-orbit interaction. In order to interpret the complex 4d Ϫ1 multiplet structure, calculations in the intermediate coupling scheme were performed taking into account the term-dependent lifetime width of each 4d Ϫ1 multiplet state. The strong influence of both the 4d-4 f exchange interaction and the term-dependent lifetime broadening on the shape of the 4d photoelectron spectrum is demonstrated. Due to the inner-shell character of the 4d and 4 f orbitals, the spectrum of atomic Eu is similar to that of Eu and Gd solid samples having the same 4 f 7 occupancy.

Heteroepitaxy and ferromagnetism of EuO/MgO (001): A route towards combined spin- and symmetry-filter tunneling

“…Figure 3 depicts the Eu 4d and 3d 3/2 core-level spectra recorded at a photon energy of hν = 6 keV and T = 33 K. Both spectra show well-resolved final-state multiplets, which agree very well with photoemission multiplets of Eu 2+ ions from experimental studies of divalent Eu compounds 15,16 and theoretical multiplet calculations. 23,24 At the high-binding-energy side, smaller spectral contributions are observable, which are part of the complex Eu 2+ final-state multiplet and do not indicate any different EuO phases, e.g., Eu 3+ ions.…”

Soft x-ray photoelectron spectroscopy study of type-I clathrates

“…The multiplet observed at low energies is the well known 9 D splitting starting with J = 2 to 6 (quintet) [24]. The featureless peak observed at higher energies is due to the 4f-4f electrostatic and the spin-orbit interactions.…”

“…For Ba encapsulated clathrates, the present study used Ba 3d resonance with on-and off-modes with the excitation of Ba 3d to 4f levels in order to investigate wave functions for constructing the Fermi surface, as discussed in the previous studies on type-I clathrate Ba 8 Si 46 and type-III clathrate Ba 24 Ge 100 [18,19]. The resonance spectroscopy of BGG has been performed, as shown in figure 4.…”

“…Our band calculations for SGG with the Sr atoms at the on-centered position also did not show any meaningful dissimilarity to that of BGG. Therefore, this case can be ruled out, and the experimental observations can be naturally interpreted by the off-centered position of the endohedral Sr atoms inside the (Ga-Ge) 24 cage, as obtained from previous neutron diffraction studies [8,12]. We then performed first-principle band calculations applying the crystal structure with off-centered endohedral Sr atoms as determined by neutron diffraction [22] for judging such possibility.…”

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

“…The Eu 4d core level spectrum is shown in Figure 2: the spectrum exhibits two main components located at higher binding energy attributed to trivalent europium and a second structure located at lower binding energy ascribed to Eu 2+ . 23 Whereas the first structure can be perfectly fitted with a Voigt function doublet with respect to europium 4d spin orbit splitting and 2:3 ratio allocated, respectively, to d 3/2 and d 5/2 states and centered at 137.2 eV, the second structure about 129 eV assigned to Eu 2+ states exhibits a more complicated asymmetric shape similar to Eu 4d core level photoemission spectrum 28 incompatible with a single Voigt function doublet approximation. Such a structure has been previously measured for different divalent and trivalent rare earth metals.…”