Systematics of f-element crystal-field interaction

摘要

Systematic behaviors of free-ion and crystal-field interactions are elucidated as a function of N, the number of f electrons in a lanthanide or actinide ion. Experimentally determined values of the free-ion interaction parameters are compared with those calculated based on Hartree-Fock theory. Comparison is also made between the lanthanide series in 4f(N) configurations and the actinide series in 5f(N) configurations. Variation in intra-ionic electrostatic interaction, spin-orbit coupling, and ion ligand interaction is analyzed in comparison between the iso-f-electron lanthanide and actinide ions. Based oil an exchange-charge model of crystal-field theory, crystal-field parameters of the f-element ions in various crystals are summarized in terms of point charge contribution and covalence effect. A systematic correlation is found between the free-ion parameters and the crystal-field strength. Increase of the crystal-field interaction results in a reduction in the free-ion parameters, (c) 2004 Elsevier Inc. All rights reserved.