title: Systematic theoretical investigation of the zero-field splitting in Gd(III) complexes: wave function and density functional approaches.
abstract: The zero-field splitting (ZFS) of the electronic ground state in paramagnetic ions is a sensitive probe of the variations in the electronic and molecular structure with an impact on fields ranging from fundamental physical chemistry to medical applications. A detailed analysis of the ZFS in a series of symmetric Gd(III) complexes is presented in order to establish the applicability and accuracy of computational methods using multiconfigurational complete-active-space self-consistent field wave functions and of density functional theory calculations. The various computational schemes are then applied to larger complexes Gd(III)DOTA(H2O)(-), Gd(III)DTPA(H2O)(2-), and Gd(III)(H2O)8(3+) in order to analyze how the theoretical results compare to experimentally derived parameters. In contrast to approximations based on density functional theory, the multiconfigurational methods produce results for the ZFS of Gd(III) complexes on the correct order of magnitude.
authors.affiliation: Department of Physics, Stockholm University, AlbaNova University Center, S-106 91 Stockholm, Sweden.
authors.forename: Shehryar
authors.initials: S
authors.lastname: Khan
authors.affiliation: Institute of Physics, Jagiellonian University, ul. Reymonta 4, PL-30-059 Krakow, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Kubica-Misztal
authors.affiliation: Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Sloneczna 54, Olsztyn PL-10710, Poland.
authors.forename: Danuta
authors.initials: D
authors.lastname: Kruk
authors.affiliation: Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
authors.forename: Jozef
authors.initials: J
authors.lastname: Kowalewski
authors.affiliation: Department of Physics, Stockholm University, AlbaNova University Center, S-106 91 Stockholm, Sweden.
authors.forename: Michael
authors.initials: M
authors.lastname: Odelius