Soft x-ray appearance potential spectra of the N4,5 transitions in lanthanum

Structure-Dependent Accessibility of Phonon-Coupled Radiative Relaxation Pathways Probed by X-ray-Excited Optical Luminescence

“…Excitation across the La N 4,5 edge (95–150 eV), corresponding to a 4d → 4f core excitation, reveals characteristic absorption features arising from the excitation of the La 3+ singlet ground state to triplet 3 D 1 (dipole forbidden but observed because of spin–orbit coupling) and singlet 1 P 1 (dipole allowed) states. , The latter feature, labeled the giant resonance, has an anomalously high absorption cross-section stemming from strong 4d–4f overlap and exhibits asymmetric broadening as a result of the short lifetime of the excited state and the activation of non-radiative Auger emission pathways. − Spectral features appearing at ca. 106 and 108 eV are a result of exchange splitting caused by the overlap of 4d and 4f wave functions resulting in triakontadipole (Δ l = 5) and octupole (Δ l = 3) higher order multipole transitions upon 4d 10 4f n → 4d 9 4f n +1 core excitation (117 eV; Δ l = 1), respectively. , While these satellite bands are relatively low in intensity in the XANES spectrum, they can be clearly resolved in total-reflection inelastic X-ray scattering measurements …”

“…106 and 108 eV are a result of exchange splitting caused by the overlap of 4d and 4f wave functions resulting in triakontadipole (Δl = 5) and octupole (Δl = 3) higher order multipole transitions upon 4d 10 4f n → 4d 9 4f n+1 core excitation (117 eV; Δl = 1), respectively. 25,26 While these satellite bands are relatively low in intensity in the XANES spectrum, they can be clearly resolved in total-reflection inelastic X-ray scattering measurements. 26 Optical luminescence arising from X-ray excitation of the lattice has been probed using X-ray-excited optical luminescence (XEOL) measurements.…”