title: Atomic origin of 3d(9)4 f(1) configuration in La(3+) solids.
abstract: We have studied the excited electronic structure of LaBr3(Ce) scintillator by soft x-ray spectroscopy such as x-ray absorption spectroscopy (XAS) and x-ray emission spectroscopy (XES). The La 3d XAS and XES spectra of LaBr3(Ce) are compared with those of other La(3+) solids (LaF3, La2O3, and La metal). From this comparison, it turns out that the La 3d XAS and XES spectra from all the La(3+) solids considered here appear at almost the same energy, even though the corresponding binding energies of the 3d core holes determined by XPS (x-ray photoelectron spectroscopy) are very different. As a result, we argue that the atomic nature of the 3d⁹4f¹ configuration created by 3d¹⁰4f⁰ → 3d⁹4f¹ x-ray absorption process in La(3+) solids is maintained via the localized 4 f (1) state, which screens the 3d core holes differently from one La(3+) solid to another.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
authors.forename: S-W
authors.initials: SW
authors.lastname: Yu
authors.forename: M H
authors.initials: MH
authors.lastname: Carpenter
authors.forename: F
authors.initials: F
authors.lastname: Ponce
authors.forename: S
authors.initials: S
authors.lastname: Friedrich
authors.forename: J-S
authors.initials: JS
authors.lastname: Lee