Theodor Schmidt and Hans Kopfermann - Pioneers in Hyperfine Physics

Systematic optical hyperfine interaction studies in various isotope series gave first indications to the possibility of single-particle and collective motions of nucleons in atomic nuclei and the variation of the nuclear radius with the mass number and deformation (isotope shift). Indeed, the careful studies by Schmidt (1908-1986), which he performed together with Schueler in Potsdam, revealed the existence of both nuclear quadrupole deformation and single-particle magnetic moments (Schmidt lines). These findings were essential as a basis for the nuclear vibrational and rotational models and the single particle shell model, respectively. The talk reviews some of the achievements of Schmidt and Kopfermann (1895-1963) and sheds some light on their working conditions before, during and after World War II