title: Communication: Relativistic Fock-space coupled cluster study of small building blocks of larger uranium complexes.
abstract: We present a study of the electronic structure of the [UO2](+), [UO2](2 +), [UO2](3 +), NUO, [NUO](+), [NUO](2 +), [NUN](-), NUN, and [NUN](+) molecules with the intermediate Hamiltonian Fock-space coupled cluster method. The accuracy of mean-field approaches based on the eXact-2-Component Hamiltonian to incorporate spin-orbit coupling and Gaunt interactions are compared to results obtained with the Dirac-Coulomb Hamiltonian. Furthermore, we assess the reliability of calculations employing approximate density functionals in describing electronic spectra and quantities useful in rationalizing Uranium (VI) species reactivity (hardness, electronegativity, and electrophilicity).
authors.affiliation: Amsterdam Center for Multiscale Modeling (ACMM), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
authors.forename: Paweł
authors.initials: P
authors.lastname: Tecmer
authors.affiliation: Laboratoire PhLAM, CNRS, UMR 8523, Université de Lille 1, Bât P5, F-59655 Villeneuve d'Ascq Cedex, France.
authors.forename: André Severo Pereira
authors.initials: AS
authors.lastname: Gomes
authors.affiliation: ETH Zürich, Laboratory of Physical Chemistry, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Knecht
authors.affiliation: Amsterdam Center for Multiscale Modeling (ACMM), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
authors.forename: Lucas
authors.initials: L
authors.lastname: Visscher