Chemical Shifts of Kα1 and Kα2 Lines in X-Ray Emission Spectra of Yb(II)/Yb(III) Fluorides: a Quantum Chemical Study

Abstract

Chemical shifts of Kα1 (2p3/2-1s1/2) and Kα2 (2p1/2-1s1/2) lines X-ray emission spectra (XES) of Yb in its fluorine compounds were calculated. Valence transition Yb(II)→Yb(III) was considered on examples of YbF2, Yb2F4, and YbF3 molecules and YbF+ 2 cation. Relativistic pseudopotential and corresponding basis sets for ytterbium have been generated and used in Hartree–Fock and DFT PBE0 calculations. The results for a threefold coordinated Yb(II) in the FYbF2YbF dimer indicate a very weak dependence of the chemical shifts on the Yb coordination number as well as on association of ytterbium difluoride molecules. The XES chemical shifts in ytterbium compounds are primarily associated with different population of the 4f-shell.