New Satellite Structure ofNd3+Ions in Rare-Earth Trichlorides

High-resolution, low-temperature absorption spectra of ${\mathrm{Nd}}^{3+}$ in various rare-earth trichlorides have been obtained in the region 4000-9000 Å. Detailed Zeeman studies were made in fields up to 36 kOe. The study concerns the properties of the sharp satellites separated from the electronic transitions by energies of 0.1 to 20 ${\mathrm{cm}}^{-1\mathrm{}}$. The dependence of these satellites upon host lattice and controlled impurities was investigated. The detailed structure of the satellites indicates near-neighbor interactions between the rare-earth ions. It is probable that the satellites are due to ${\mathrm{Nd}}^{3+}$ ions in distorted sites near crystal imperfections, in particular, dislocations.