Understanding the O-4,O-5 edge structure of actinide metals: Electron energy-loss spectroscopy and atomic spectral calculatio...

Using electron energy-loss spectroscopy (EELS) and many-electron atomic spectral calculations, we examine the O-4,O-5 (5d -> 5f) edge structure of the ground-state alpha phase of Th, U, Np, Pu, Am, and Cm metals. Results show that (i) atomic calculations explain the trend in O-4,O-5 structure along the actinide series and (ii) the dipole-allowed transitions are contained within the giant resonance. Therefore, the small prepeak in the 5d -> 5f transition of Th, U, and Np should not be labeled the O-5 peak, but rather the Delta S=1 peak. In presenting the O-4,O-5 EELS spectra for Np, Am, and Cm, we extend the known d -> f transitions for actinide metals.