Spectrum of Er3+ in LaCl3

Abstract

The energy levels of the Er3+ ion in LaCl3 are calculated by finding the eigenvalues of the matrices for the combined Coulomb, spin—orbit, and crystal‐field interactions within the f 11 configuration. For suitably chosen values of the three Slater integrals and the spin—orbit coupling constant the root‐mean‐square deviation between the calculated and the experimental positions of 20 terms is 140 cm−1. Crystal‐field parameters can be chosen which reduce the root‐mean‐square deviation between the calculated and the measured splittings of 72 levels to 3.84 cm−1. Zeeman splitting factors in the direction parallel to the crystal axis are also calculated. The results for Er3+ in LaCl3 are compared with those for Nd3+ in LaCl3.