Search for intermultiplet transitions in USb

Resonant inelastic x-ray spectroscopy on UO2 as a test case for actinide materials

“…In fact, we observe a strong excitation for ΔJ = 2, for 3 H 4 → 3 F 2 at ∼520 meV, but a weak one for 3 H 4 → 3 H 5 at ∼920 meV (a slightly stronger signal, shown in figure 1 inset, was observed at this position when the incident energy was tuned at the N 5 edge at 736 eV). This is exactly the opposite of the situation with neutrons, where the first excited level is non-dipolar, so is predicted to be weak [13,14], and the second excitation should be stronger; however, energy transfers up to 1 eV face difficulties due to the restrictions of the form factor in neutron studies [11]. The resonant process has no form factor, and x-rays are not subject to the kinematical restrictions present in neutron scattering due to the finite mass of the neutron.…”

“…have been very successful [10,11]. Efforts have been made on uranium systems UPd 3 [12], UPt 3 [12], and USb [13]. Later, problems of noise at high energies were found with one of the spectrometers at the ISIS neutron source [14].…”

Resonant x-ray spectroscopy of uranium intermetallics at the M4,5 edges of uranium

“…Intermultiplet transitions represent another possible method 7,8 , which is again successful for the lanthanides , but since the energies separating the ground and first-excited states for the actinides are larger than in the lanthanides (greater spin-orbit splitting and also greater crystal-field potential for the actinides), the experiments are that much harder. Again only a few successful studies are reported on UPd 3 9 and on URu 2 Si 2 10 , and those only for 5f 2 systems, where the first excited level is ∼ 400 meV, whereas for 5f 3 configurations these excited levels are expected to be in the range of 550−750 meV 11 and have not yet been observed directly.…”