One. Paramagnetic Ions of Transition Elements. - 1. Paramagnetism of incomplete electronic shells. - 2. Level splitting of free paramagnetic ions. The Zeeman effect. - 3. Level splitting of free atoms in an external electric field. The Stark effect. - Two. Levels of Paramagnetic Ions in Crystal Lattices and Magnetic Fields. - 1. Macroscopic description of crystal systems. Symmetry of crystals. - 2. Symmetry point groups. - 3. Representations of groups. - 4. Group-theoretical classification of levels in fields of various symmetries. - 5. Application of the interaction Hamiltonian to the calculation of initial splitting. - 6. Paramagnetic ions in crystal fields. Splitting of energy levels. - 7. Qualitative picture of level splitting in a static magnetic field. - 8. Application of spin Hamiltonians. Angular dependence of EPR spectra. - Three. Electron Paramagnetic Resonance. - 1. Phenomenological treatment of EPR. - 2. Dynamic theory of paramagnetic resonance. - Four. EPR Line Shapes and line Widths. - 1. Dipole-dipole interactions. - 2. Exchange interactions. - 3. Application of the method of moments to analysis of EPR line shapes. - Five. Relaxation Processes in Paramagnetic Crystals. - 1. Spin-lattice relaxation. - 2. Relaxation associated with spin-spin interactions. - 3. Multiple cross-relaxation transitions and harmonic cross-relaxation. - 4. Level population changes due to cross-relaxation processes. - 5. Spin-lattice relaxation of ions of the 4f-and 3d-transition groups. - Six. Paramagnetic Single Crystals as Active Elements in Quantum Paramagnetic Amplifiers (QPA). - 1. Operating principles of QPA. - 2. Requirements from paramagnetic crystals in QPA. - 3. Formation of local symmetry centers in the synthesis of paramagnetic single crystals. Language: English