Extraction of crystal-field parameters for lanthanide ions from quantum-chemical calculations

TL;DR

This paper introduces a straightforward quantum-chemical method to derive crystal-field and spin-orbit parameters for lanthanide ions in various host crystals, enabling accurate modeling even in low-symmetry environments.

Contribution

The paper presents a new simple approach to construct effective Hamiltonians for lanthanide ions from quantum-chemical calculations, applicable to complex low-symmetry sites.

Findings

Good agreement between calculated and fitted crystal-field parameters.

Method successfully applied to multiple host crystals with different symmetries.

Effective for low-symmetry sites with many parameters.

Abstract

A simple method for constructing effective Hamiltonians for the 4fN and 4fN-15d energy levels of lanthanide ions in crystals from quantum-chemical calculations is presented. The method is demonstrated by deriving crystal-field and spin-orbit parameters for Ce3+ ions doped in LiYF4, Cs2NaYCl6, CaF2, KY3F10 and YAG host crystals from quantum chemical calculations based on the DV-X{\alpha} method. Good agreement between calculated and fitted values of the crystal-field parameters is obtained. The method can be used to calculate parameters even for low-symmetry sites where there are more parameters than energy levels.