DFT calculations of crystal-field parameters for the lanthanide ions in theLaCl3 crystal

Abstract

We present herein a calculation of crystal-field (CF) parameters for the lanthanide ions in theLaCl3 crystal, using the density functional theory-based orbital-free embedding formalism inconjunction with the effective Hamiltonian method. The calculated values for thesecond- and fourth-rank CF parameters agree fairly well with the experimental data. It isfound that the effect of ligand polarization plays a crucial role in determining the sign andmagnitude of the second-rank CF parameters, while the effect of Pauli repulsion between 4felectrons and the ligands is important for the fourth-rank CF parameters. The usefulnessof the present approach is illustrated by a study of the relative preference ofEu3 + occupation onthe two distinct Pb2 + sites in the KPb2Cl5 crystal. The computational approach and results discussed in this work are useful for abetter understanding and simulation of the CF effect in the lanthanide-containing systems.