Double-vacancy excitations in the L atomic levels of Pr and Sm

Discontinuities resulting from the simultaneous creation of two electronic vacancies in the L atomic shells of praseodymium and samarium were observed in the x-ray absorption spectra of these elements. These discontinuities were identified as being the results of the double excitations (2s^-1+2p1/2^-1), (2s^-1+2p3/2^-1), and (2p1/2^-1+2p3/2^-1), and their measured energies were found to be in good agreement with the results of relativistic Hartree-Fock-Slater calculations. The magnitude of these discontinuities, although difficult to determine, is about fifty times smaller than the magnitude of the discontinuity at the L₃-absorption edge of the element.