Lanthanide Crystal Field Theory in the J-Mixing Regime: fn Configurations
Abstract
The low-energy sector of the lanthanide fn shell is to first approximation governed by the interplay of three interactions: Coulomb repulsion, spin-same-orbit coupling and the ligand crystal field potential. To rationalize the energy landscape in different chemical environments, it is desirable to extract the phenomenological crystal field parameters from experimental data; however, in practice, high-dimensional fitting procedures complicate their routine determination. Here, we present a computational extraction procedure based on real tensorial sets and the U(7) canonical chain that, unlike existing operator equivalent methods, takes all J multiplets of the lowest-energy LS term into account, ensuring meaningful results even in the presence of considerable J-mixing. Two series of lanthanide compounds, [Ln(III)(C8H8)2]-} and doped Ln(III):Y2O3} (Ln ∈ {Ce, Pr, Nd, Sm, Eu}) serve as examples for high- (D8h) and low-symmetry (C2) scenarios. Consequences for the generalisation toward actinides are briefly discussed.
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BibTeX
@misc{safari2026lanthanide,
title = {{Lanthanide Crystal Field Theory in the J-Mixing Regime: $f^n$ Configurations}},
author = {Arta A. Safari and Markus Reiher},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.35622},
eprint = {2610.35622},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.35622},
}
RIS
TY - UNPB
TI - Lanthanide Crystal Field Theory in the J-Mixing Regime: f^n Configurations
AU - Arta A. Safari
AU - Markus Reiher
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.35622
UR - https://arxiv.org/abs/2610.35622
AB - The low-energy sector of the lanthanide f^n shell is to first approximation governed by the interplay of three interactions: Coulomb repulsion, spin-same-orbit coupling and the ligand crystal field potential. To rationalize the energy landscape in different chemical environments, it is desirable to extract the phenomenological crystal field parameters from experimental data; however, in practice, high-dimensional fitting procedures complicate their routine determination. Here, we present a computational extraction procedure based on real tensorial sets and the U(7) canonical chain that, unlike existing operator equivalent methods, takes all J multiplets of the lowest-energy LS term into account, ensuring meaningful results even in the presence of considerable J-mixing. Two series of lanthanide compounds, [Ln(III)(C_8H_8)_2]^-} and doped Ln(III):Y_2O_3} (Ln ∈ {Ce, Pr, Nd, Sm, Eu}) serve as examples for high- (D_8h) and low-symmetry (C_2) scenarios. Consequences for the generalisation toward actinides are briefly discussed.
ER -