SMEKAL, ADOLF GUSTAV STEPHAN

(b. Vienna, Austria, 12 September 1895: d. Graz, Austria, 7 March 1959)

physics.

Adolf Smekal was the elder child and only son of Gustav Smekal, an artillery officer. Because of repeated shifts of residence, he gained admission to university study by the “back door” of a Realschule diploma (1912) and a year at the Technische Hochschule in Vienna (1912–1913). He then attended the University of Graz for four years, receiving his doctorate (14 June 1917) under Michael Radakovič, to whose family the Smekals were closely related. Extreme nearsightedness had rendered Smekal unfit for military service. Yet neither that handicap nor his short stature prevented the young man from becoming a skilled and tireless alpinist, who however in middle age succumbed to corpulence and heart disease.

From the autumn of 1917 to the spring of 1919 Smekal continued his study of mathematics and physics at the University of Berlin. In June 1919 he took up an assistantship in the physical institutes of Heinrich Mache and Ludwig Flamm at the Technische Hochschule in Vienna, where he immediately joined the circle of young theorists around Hans Thirring at the university. In the autumn of 1920 Smekal accepted an assistantship to Gustav Jaeger at the university, where he qualified simultaneously as Privatdozent in both theoretical and experimental physics. The following year this venia legendi was extended to the Technische Hochschule, where in 1923 Smekal was appointed Honorardozent in the newly established Abteilung für Technische Physik.

In the autumn of 1928 Smekal was appointed professor of theoretical physics at the University of Halle. He was especially pleased by the experimental facilities of the institute attached to that post, in which he continued until deported by the Americans to West Germany in June 1945. After some years of professional and financial uncertainty, Smekal obtained a chair and institute of his own in 1949 at the University of Graz, as professor of experimental physics. Smekal married twice, in 1924 and 1942, and had one child of the latter marriage.

Like virtually all Austrian theoretical physicists of his generation, Smekal was thoroughly trained in statistical mechanics: and his first publications were on the foundations of quantum statistics. (His doctoral dissertation aimed to show “that such radical assumptions as those of the quantum theory are by no means necessary in order to avoid the equipartition of energy.”) Smekal also assimilated, and soon exemplified, the Austrian critical-encyclopedic style. In the 1920’s he was the principal abstractor of publications on quantum theory for the Physikalische Berichte and wrote several extraordinarily learned handbook articles and a veritable fountain of research papers that, although distinguished for their recherché bibliographic citations, generally were conceptually derivative and often lacking in physical as well as personal “tact.”

The year and a half in Berlin (1917–1919) was extremely important for Smekal’s scientific development and subsequent research. There he took up the quantum, the Bohr theory, and the problem of X-ray spectra. After delivering a crushing blow to the faltering Sommerfeld-Debye theory, which deduced X-ray spectra from hypothetical intra-atomic mechanisms, Smekal, in competition with Dirk Coster and Gregor Wentzel, induced from the experimental data the number, arrangement, and allowed transitions between the atomic energy levels resulting in X-ray spectral lines.

Although these papers of 1920–1921 are probably his most original achievement as a theorist, Smekal’s name is better known through the effect predicted by him in September 1923 and discovered experimentally by C. V. Raman in 1928. This is the alteration of the frequency of light upon being scattered by an atomic-molecular system—a decrease, or increase, by an amount equal to the frequency of the light that would be absorbed or emitted in transitions between the stationary states of that system. It was the radical light quantum viewpoint that enabled Smekal to foresee this effect; but its necessity was immediately accepted also by theorists who rejected that viewpoint, particularly those around Niels Bohr. Smekal implied that his considerations were independent of A. H. Compton’s. he did not, however, preclude influence from William Duane, with whose particulate theory of X-ray diffraction Smekal’s consideration appear to bear considerable affinity.

Smekal’s interest in the great discrepancy between the mechanical strength of ideal and of real crystals, apparently aroused by contact with the Austro-Hungarians staffing the Kaiser-Wilhelm-Institut für Faserstoffchemie in Berlin, was first expressed in a paper extending A. A. Griffith’s theory of fracture (1922). There Smekal first advanced his conception of irregularities in the structure of real crystals arising as a “frozen Brownian molecular motion.”¹ After 1925 he advocated a kind of “universal remedy”² in solid-state physics. In 1925–1927 Smekal turned from fundamental questions in quantum theory and atomic physics to the technical physics of structure-dependent properties of solids. By 1933 he had become, and at his death he remained, a world authority on brittleness and the technology of pulverization.

NOTES

1. A. Smekal, “Kristalleigenschaften und Kristallisationsbedingungen,” in Forschungen and Fortschritte, 5 (1929), 385–387.

2. A. Joffé, letter to the editor, Naturwissenschaften16 (1928) 744–745. Cf. Joffé, Begegnungen mit Physikern(Leipzig, 1967), 83–84.

BIBLIOGRAPHY

I. Original Works. The only bibliography of Smekal’ publications is in Poggendorff, V , 1176; VI , 2473–2474; and VII , 427–429. Smekal’s most important monograph is “Allgemeine Grundlagen der Quantenstatistik and Quantentheorie.” in Encyklopädie der mathematischen Wissenschaften. V , pt. 3 (Leipzig, 1926), 816–1214. His papers on the X-ray term scheme. “Zur Feinstruktur der Röntgenspektren,” in Zeitschrift für, Physik4 (1920). 26–45. and 5 (1921), 1–106 are based upon ‘le système de Smekal” (adopted by the marginal French but not by better-informed theorists), according to which every degree of freedom of every electron in an atom is entitled to its own quantum number. Smekal’s prediction of the Raman effect is “Zur Quantentheorie der Dispersion,” in Naturwissenschaften, II (1923), 873–875: and his initial publication on fracture theory is “Technische Festigkeit und molekulare Festigkeit,” ibid., 10 (1922), 799–804.

II. Secondary Literature. The informative obituaries are by Ludwig Flamm: Almanach. Österreichische Akademie der Wissenschaften, 109 (1959), 421–427; Acta physica austriaca, 13 (1960), 140–143; Technische Hochschule, Vienna, 150 Jahre Technische Hochschule in Wien, 1815–1965 (Vienna, 1965), I, 359–361, and II . 166. See also H. Rumpf, “Zur Entwicklungsgeschichte der Physik der Brucherscheinungen: A. Smekal zum Gedächtnis,” in Chemie-Ingenieur-Technik, 31 (1959), 697–705; and A. Faessler. “Adolf Smekal,” in Glastechnische Berichte, 32 (1959), 180. For Smekal’s criticism of the Debye-Vegard theory of X-ray spectra, see John L. Heilbron. “The Kossel-Sommerfeld Theory and the Ring Atom,” in Isis, 58 (1967), 451–485.

Paul Forman