Double-vacancy excitations in theLatomic levels of neodymium

Abstract

The x-ray absorption spectrum of neodymium exhibits discontinuities which are the results of multielectronic excitations in the $L$ atomic shells of the elements. The observed discontinuities were identified as being the results of $2{s}^{\ensuremath{-}1}+2{p}_{\frac{1}{2}}^{\ensuremath{-}1}$, $2{s}^{\ensuremath{-}1}+2{p}_{\frac{3}{2}}^{\ensuremath{-}1}$, $2{p}_{\frac{1}{2}}^{\ensuremath{-}1}+2{p}_{\frac{3}{2}}^{\ensuremath{-}1}$, $2{p}_{\frac{1}{2}}^{\ensuremath{-}2}$, and $2{p}_{\frac{3}{2}}^{\ensuremath{-}2}$ double excitations. Two discontinuities which correspond in energy to the simultaneous creation of three electronic vacancies were noted. The measured energies and the results of relativistic Hartree-Fock-Slater calculations for double-vacancy excitations are in good agreement. The magnitude of these discontinuities is difficult to determine with reasonable certainty, but it is only a few percent of the discontinuity and the ${L}_{3}$ absorption edge of the element.