  Rare-earth (RE) based compounds and alloys are of great interest both for
their fundamental physical properties and for applications. In order to tailor
the required compounds for a specific task, one must be able to predict the
energy level structure and transition intensities for any magnetic ion in any
crystalline environment. The crystal-field (CF) analysis is one of the most
powerful theoretical methods to deal with the physics of magnetic ions. In the
present work, this technique is used to analyze peculiar physical properties of
some materials employed in the production of new-generation solid-state laser
and high-performance permanent magnets.
