First direct calculation of 4f‘ 4f oscillator strengths for dipolar electric transitions in PrCl3

In two previous papers, we interpreted completely the crystal field splitting and Zeeman data of trivalent praseodymium ions in PrCl₃ taking into account configuration interaction between 4f², 4f5d and 4f6p. The obtained eigenvectors are now used to calculate directly the oscillator strengths originating from dipolar electric processes between opposite parity configurations, giving rise to apparent 4f ‘4f transitions. The calculation reproduces in a satisfactory way the absorption from the ground levels toward the ³P₂ and ¹D₂ multiplets but not toward ³P₀ and ³P₁.