Configuration Interaction and the Spectra of LaCl3:Pr3+

Abstract

Effective operators, which take into account the excitation of a $4f$ electron to a higher-lying $p$ or $f$ orbital by means of the crystal field, are cast into a form which is convenient for a parametric study. The complete crystal-field matrices of these operators and of the operators that arise in the first-order analysis are diagonalized, and the Stark levels of La${\mathrm{Cl}}_3$: ${\mathrm{Pr}}^{3+}$ are fitted parametrically. It is found that when the effect of configuration interaction is absorbed by these new parameters, the ordinary crystal-field parameters change by a small but significant amount.