Publisher Information: 1933.
Stern, Otto (1888-1969); Otto Robert Frisch (1904-79) Über die magnetische Ablenkung von Wasserstoffmolekülen und das magnetische Moment des Protons. I. Offprint from Zeitschrift für Physik 85 (1933). 4-16pp. Original printed wrappers, slightly spotted. Very good.
First Edition, Offprint Issue. Using the molecular beam method he had developed in the 1920s, Stern and his collaborators became the first to measure the magnetic moment of the proton, as announced in the present paper (Stern’s follow-up paper, written with Immanuel Esterman, was published in the Zeitschrift a few months later). Stern received the Nobel Prize for physics in 1943 for this achievement; his co-author, Otto Frisch, went on to play a crucial role in the discovery of nuclear fission.
Between 1923 and 1933, when Stern was professor of physical chemistry at Hamburg, he headed a program devoted to molecular-beam research. In the early 1930s he set out to test the validity of Dirac’s theory that “the ratio of the magnetic moment of the proton to that of the electron should have been the same as the inverse ratio of their masses. This theory was believed so generally that when Stern, O. R. Frisch, and [Estermann] began the very difficult experiments, they were told more than once that they were wasting their time and effort. But Stern’s perseverance paid off. Measurements showed a proton magnetic moment two or three times larger than expected . . . It is this work that was specifically mentioned in Stern’s Nobel Prize citation” (Dictionary of Scientific Biography).
The proton’s unexpectedly large magnetic moment remained a puzzle until the development of quark theory in the 1960s. It is now known that protons and neutrons are not elementary particles as once thought, but are composed of quarks, and the magnetic moments of the quarks can be used to compute the magnetic moments of the proton and neutron. Ezhela et al., Particle Physics: One Hundred Years of Discoveries, p. 69.Book Id: 50962