title: Electronic spectrum of UO2(2+) and [UO2Cl4]2- calculated with time-dependent density functional theory.
abstract: The electronic spectra of UO(2) (2+) and [UO(2)Cl(4)](2-) are calculated with a recently proposed relativistic time-dependent density functional theory method based on the two-component zeroth-order regular approximation for the inclusion of spin-orbit coupling and a noncollinear exchange-correlation functional. All excitations out of the bonding sigma(u) (+) orbital into the nonbonding delta(u) or phi(u) orbitals for UO(2) (2+) and the corresponding excitations for [UO(2)Cl(4)](2-) are considered. Scalar relativistic vertical excitation energies are compared to values from previous calculations with the CASPT2 method. Two-component adiabatic excitation energies, U-O equilibrium distances, and symmetric stretching frequencies are compared to CASPT2 and combined configuration-interaction and spin-orbit coupling results, as well as to experimental data. The composition of the excited states in terms of the spin-orbit free states is analyzed. The results point to a significant effect of the chlorine ligands on the electronic spectrum, thereby confirming the CASPT2 results: The excitation energies are shifted and a different luminescent state is found.
authors.affiliation: Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Heverlee-Leuven, Belgium. kristin.pierloot@chem.kuleuven.be
authors.forename: Kristine
authors.initials: K
authors.lastname: Pierloot
authors.forename: Els
authors.initials: E
authors.lastname: van Besien
authors.forename: Erik
authors.initials: E
authors.lastname: van Lenthe
authors.forename: Evert Jan
authors.initials: EJ
authors.lastname: Baerends