Beschreibung
First edition, complete journal issue in original printed wrappers, of Heisenberg's first published paper, describing his 'core model' of the atom and its application to solve the problems of the multiplet structure in atomic spectra and the anomalous Zeeman effect, which had defeated all previous attempts. "Just a year after entering Sommerfeld's program, Heisenberg amazed his teacher by presenting a model of atoms that seemed to resolve every spectroscopic riddle at a stroke. But the model succeeded only because its daring inventor failed to follow the requirements of an acceptable quantum theory" (Cassidy, Beyond Uncertainty, p. 95). Sommerfeld's own attempt to solve the same problems precedes Heisenberg's paper in the same issue. "The Bohr theory of atoms and molecules, Sommerfeld's quantum theory of spectral lines, and the correspondence principle of 1918 . . . formed the foundations of the Bohr quantum theory. This theory provided in turn the basis for model interpretations of most, but not all, existing phenomena of empirical spectroscopy. Two phenomena, multiplet line spectra and the anomalous Zeeman effect, continually resisted explanation by quantized mechanical models" (Cassidy, pp. 191-192). "The eighteen-year-old Heisenberg entered Sommerfeld's institute in the winter semester of 1920-21, and Sommerfeld immediately introduced him to the Bohr theory. In June 1921 Alfred Landé gave a phenomenological explanation of the splittings observed in the anomalous Zeeman effect, but he did not propose any physical interpretation of his theory, writing to Bohr: With regard to the complicated types of the Zeeman effect, I have found a few empirical rules which . . . permit one to make predictions regarding the neon spectrum. But what these rules signify is entirely incomprehensible to me. Sommerfeld suggested that Heisenberg should try to find a model to explain Landé's rules. The result was the present paper, submitted in his third semester, when he was just twenty years old. In it he claimed that he was presenting the essential details of a complete quantum-theoretical model interpretation of the empirical regularities of optical multiplet lines in spectroscopy and the anomalous Zeeman effect of these lines in a magnetic field. All previous attempts to explain these lines by mechanical models had failed . . . The model was nevertheless riddled with what Max Born called conscious deviations from accepted principles and procedures. Heisenberg, Sommerfeld's vastly gifted pupil, had reduced the previously inexplicable line structure to internal magnetic interactions between the valence electrons and the rest of the atom. The inner orbits and nucleus acted as a solid core . . . possessing on the average a half-unit of angular momentum. Half-integral quantum numbers and magnetic interactions between orbital interactions between orbital electrons had already appeared in the work of Landé and others, but half-integral momenta and a magnetic core had not. They could not be justified in either classical or quantum theory, despite Sommerfeld's blessing. Although the model was theoretically untenable, with it Heisenberg could quantitatively account for doublet and triplet term energies. By attributing half-integral angular momenta to the valence electrons, he could also derive the semi-empirical Landé g-factors for the anomalous Zeeman effect and their continuous transition to unity in the Paschen-Back effect" (ibid., pp. 190-1). David C. Cassidy, Heisenberg's first core model of the atom: the formation of a professional style, pp. 187-224 in Historical Studies in the Physical Sciences, Vol. 10 (1979). 8vo, pp. 257-362. Original printed wrappers (spine ends worn with slight loss, lower inner corner bumped). Bestandsnummer des Verkäufers ABE-1475084467556
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