Computer calculations of the fine electronic structure and properties of 4f/5f-electron compounds

We would like to demonstrate the abilities of our calculation package BIREC 1.5 (Basic Interactions in Rare Earth Compounds), that has been developed in Center for Solid State Physics. This program allows to calculate many of magnetic and electronic properties of compounds containing rare-earth atoms. The main assumption of the used approach is the fundamental role of the local symmetry of the environment of the paramagnetic ion in the crystal, taken into account by using the Crystal Electric Field (CEF) formalism. The package allows to obtain the discrete (fine) electronic structure of RE-ions which determines magnetic and electronic properties of the whole compound, e.g., the specific heat and the magnetic entropy, the magnetic moment and its behavior in external magnetic fields, the magnetic susceptibility and its anisotropy, the probability of inelastic-neutron-scattering transitions, the spin and orbital moments of the RE ions and many more. Program BIREC allows calculations of magnetic and electronic properties of compounds containing rare-earth atoms, both in inter-metallic and ionic compounds. (author)