Relativistic effects on the electronic structure and chemical bonding of UF6

• Published in: The Journal of chemical physics 1993-11, Vol.99 (9), p.6810-6817
• Main Authors: ONOE, J, TAKEUCHI, K, NAKAMATSU, H, MUKOYAMA, T, SEKINE, R, KIM, B.-I, ADACHI, H
• Format: Article
• Language: English
• Subjects: Atomic and molecular physics; Calculations and mathematical techniques in atomic and molecular physics (excluding electron correlation calculations); Corrections to electronic structure; Density-functional theory; Electronic structure of atoms, molecules and their ions: theory; Exact sciences and technology; Physics; Relativistic and quantum electrodynamic effects in atoms and molecules
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.465824

We have studied the relativistic effects in the electronic structure and chemical bonding for the ground state of UF6, using the relativistic and nonrelativistic discrete-variational Xα molecular orbital calculations. It is found that two relativistic effects appear in the valence levels; the energy level splitting and upward shift of energies of the molecular orbitals. From the Mulliken population analysis of the valence levels, it is shown that the level splitting is due to mixing of the uranium atomic orbitals with a strong spin–orbit interaction, such as U6p, and the upward shift due to the increase in the screening of the nuclear charge and charge redistribution. The strength of U–F bonding remarkably increases for the relativistic case, because the changes in the radial distributions due to the relativistic effects induce both the decrease in the antibonding interactions and the increase in the bonding ones.