Calculation of the crystal field splittings of Sm3+ levels in LaCl3 with inclusion of J mixing

A complete diagonalization of the matrices for the electrostatic, spin‐orbit, and crystal field interactions for Sm³⁺ in LaCl₃ has been carried out using a truncated set of basis vectors containing 42 of the 73 LS states. This diagonalization allowed many new assignments to be made. Corrections of some of the centers of gravity previously used in a fit of free ion parameters was also possible. The newly obtained free ion parameters are more in accord with the trends for the other lanthanide ions in LaCl₃. They reduce the rms deviation from 119 to 54 cm⁻¹. The parameters (in cm⁻¹)used in the final diagonalization are $E^1{\text{=5465.27 ± 17.21, E}}^2{\text{=25.40 ± 0.39, E}}^3{\text{=547.62 ± 1.65, ζ=1153.8 ± 8.9, a=24.29 ± 1.98, β=−795.72 ± 98.4, γ=800, B}}_0^2{\text{=161.70, B}}_0^4{\text{=−182.00, B}}_0^6{\text{=−710.24, B}}_6^6\text{=448.14}$ .