Gendron F, Autschbach J. Puzzling Lack of Temperature Dependence of the PuO
2 Magnetic Susceptibility Explained According to Ab Initio Wave Function Calculations.
J Phys Chem Lett 2017;
8:673-678. [PMID:
28112941 DOI:
10.1021/acs.jpclett.6b02968]
[Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The electronic structure and the magnetic properties of solid PuO2 are 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 PuO2 can 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.
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