An ab initio theoretical study of the electronic structure of UO2+ and [UO2(CO3)3]5-
2009 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, Vol. 113, 1420-1428 p.Article in journal (Refereed) Published
The electronic spectra up to 50000 cm-1 of uranyl(V) both as a bare ion, UO21, and coordinated with three carbonate ligands, [UO2(CO3)3]5-, are presented. Solvent effects were treated by a nonequilibrium continuum solvent model. The transition energies were obtained at the spin-orbit level using relativistic wave function based multiconﬁgurational methods such as the complete active space self-consistent ﬁeld method (CASSCF) and the complete active space with second-order perturbation theory (CASPT2) followed by a calculation of the spin-orbit effects at the variation-perturbation level. Earlier relativistic intermediate Hamiltonian Fock space coupled-cluster calculations on the spectrum of the bare uranyl(V) ion were extended to investigate the inﬂuence of electron correlation effects on spacings between the electronic states. This study is an attempt to contribute to an enhanced understanding of the electronic structure of actinyl ions. Both spectra show transitions within nonbonding orbitals and between nonbonding and antibonding orbitals as well as charge transfers from the uranyl oxygens to uranium. The ground state in UO2+ is found to be 2Φ5/2u, corresponding to the σu2φu1 conﬁguration, while in [UO2(CO3)3]5-, it is 2∆3/2u, arising from the σu2δu1 conﬁguration. It is remarkable that the excited state corresponding to an excitation from the nonbonding δu to the uranyl antibonding 3πu* molecular orbital is signiﬁcantly lower in energy in the carbonate complex, 6623 cm-1, than that in the bare ion, 17908 cm-1. The ﬁrst ligand (carbonate) to metal charge-transfer excitation is estimated to occur above 50000 cm-1. The reported results compare favorably with experiment when available.
Place, publisher, year, edition, pages
American Chemical Society , 2009. Vol. 113, 1420-1428 p.
Research subject Quantum Chemistry
IdentifiersURN: urn:nbn:se:su:diva-32092DOI: 10.1021/jp809108hISI: 000263529600003OAI: oai:DiVA.org:su-32092DiVA: diva2:279448