X-ray emission spectra (XES) due to the rare-earth 4d --> 2p(1/2)(L ga
mma(1)) and 4d --> 2p(3/2)(L beta(2,15)) electronic transitions in rar
e-earth compounds have been investigated experimentally by using an X-
ray as an incident excitation source. The large exchange interaction b
etween a 4d core hole and a 4f electron in the final state in the emis
sion process brings about a satellite on the low energy side of the ma
in band, even though the intensity of the satellite in Ce compounds is
very weak. In general, the intensity ratio of the satellite to the ma
in band in the L gamma(1)-XES is larger than that in the L beta(2,15)-
XES, which is conspicuous in heavy rare-earth compounds. Experimental
results are compared with the theoretical calculation.