title: Puzzling Lack of Temperature Dependence of the PuO2Magnetic Susceptibility Explained According to Ab Initio Wave Function Calculations.
abstract: The electronic structure and the magnetic properties of solid PuO2are investigated by wave function theory calculations, using a relativistic complete active space (CAS) approach including spin-orbit coupling. The experimental magnetic susceptibility is well reproduced by calculations for an embedded PuO812-cluster model. The calculations indicate that the surprising lack of temperature dependence of the magnetic susceptibility χ of solid PuO2can be rationalized based on the properties of a single Pu4+ion in the cubic ligand field of the surrounding oxygen ions. Below ∼300 K, the only populated state is the nonmagnetic ground state, leading to standard temperature-independent paramagnetism (TIP). Above 300 K, there is an almost perfect cancellation of temperature-dependent contributions to χ that depends delicately on the mixing of ion levels in the electronic states, their relative energies, and the magnetic coupling between them.
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York , Buffalo, New York 14260-3000, United States.
authors.forename: Frédéric
authors.identifier: http://orcid.org/0000-0002-1896-3978
authors.initials: F
authors.lastname: Gendron
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York , Buffalo, New York 14260-3000, United States.
authors.forename: Jochen
authors.identifier: http://orcid.org/0000-0001-9392-877X
authors.initials: J
authors.lastname: Autschbach