The hydrogen atom, relativistic effects ad spin. Identical articles and symmetry. Many electron atoms coupling schemes and vector model. see man effect hyperfine structure. The diatomic molecule, the frank condon principle, z-ray diffraction, Microwave methods, resonance phenomena, ESR, NMR and optical pumping and Mossbauer scattering. General concepts of spectroscopy for NQ, ESR infrared and Raman spectroscopy