SELECTIVE DEEXCITATION OF THE 4D(9)4F(N+1) EXCITED-STATES STUDIED BY RESONANT PHOTOEMISSION IN LACL3 AND CECL3

Resonant photoemission in the rare-earth 4d4f prethreshold absorption region has been investigated in LaCl3 and CeCl3. It is found that the intensity ratio of the rare-earth 5p1/2 photoemission to the total 5p emission deviates from the statistically expected value in the prethreshold absorption region and depends on the final multiplet states of the 4d4f photoexcitation. The ratio reaches 0.7 at the 4d94f1 (3D1) photoexcitation in LaCl3 and nearly 0.5 at the 106-eV photoexcitation in CeCl3. In CeCl3, it is also found that the magnitudes of the resonant enhancements of the Ce 4f emission are not proportional to the strengths of the 4d4f photoabsorption lines. These resonant aspects are explained by the multiplet dependence of the Auger transition probability involved in the resonant photoemission. © 1994 The American Physical Society.