Karl Wilhelm Meissner

Karl Wilhelm Meissner (born December 15, 1891 in Reutlingen , † April 13, 1959 ) was a German-American physicist .

Life

ancestry

Karl Wilhelm Meissner was born on December 15, 1891 in Reutlingen. His father, Karl Emil Meissner, worked as a bookseller at the Reutlingen book printing and publishing house Ensslin & Laiblin. The family was Protestant.

education

Karl Wilhelm Meissner studied physics in Tübingen and Munich. During his studies, he became a member of the fraternity A. V. Virtembergia in Tübingen . Meissner received his doctorate from the well-known spectroscopist Friedrich Paschen on July 30, 1915 with the dissertation Investigations and wavelength measurements in the red and infrared spectral range . As a student, Meissner had entered the world of science with a bang, because he proved that oxygen occurs in the sun .

First activities

But he could not find a scientific job after his doctorate and had to accept a teaching position at the secondary school in Cannstatt . From 1916, however, he became a research assistant at the Physics Institute of the University of Zurich with Edgar Meyer . Here Meissner turned to researching the spectrum of the noble gas neon . With the results of this research, Meissner was able to complete his habilitation in 1918.

marriage

In Zurich, Meissner met the Jewish-Polish physics doctoral student Ita Blima Kohn. Meissner and Kohn married on September 27, 1919.

Career

In 1925, Meissner was appointed first assistant to the Physics Institute at the University of Frankfurt am Main (Director: Richard Wachsmuth ) and as a non-official associate professor at the University of Frankfurt. After the professor emeritus for astronomy, Martin Brendel , Meissner was appointed full professor for astronomy at the University of Frankfurt in 1927. The calling brought with it a lot of work. Not only did he have to represent astronomy and astrophysics at the University of Frankfurt, but also continue to perform his previous tasks in the Physics Institute (e.g. higher experimental physics). After Wachsmuth retired in 1932, Meissner was appointed full professor for experimental physics and director of the Physics Institute.

Here in Frankfurt, Meissner developed a fruitful and extremely successful research activity since 1925. After researching the neon spectrum, he turned to researching the argon spectrum. In order to penetrate further into the secrets of the atomic structure , an important task was to continuously improve the accuracy of the spectroscopic investigations. In this context he developed the so-called atomic beam method (simultaneously and independently of R. Minkowski and H. Bruck) and was able to record spectra with unprecedented accuracy. With this aid, Meissner researched the so-called hyperfine structure of the spectra and was able to determine the magnetic moment of an atomic nucleus ( potassium ) for the first time from spectroscopic data .

time of the nationalsocialism

With the National Socialist seizure of power in 1933, troubled times began for the Meissner couple, as Ms. Meissner was of Jewish descent. Karl Wilhelm Meissner, however , was not affected by the " Law for the Restoration of the Professional Civil Service ", which the Nazi government used to oust Jewish professors from the universities, since it did not contain a paragraph for the case of marriage to a Jewish wife. and had an undisputed position at the Frankfurt University due to his excellent research and the popularity of his lectures. But this suddenly changed when a fundraiser for the NS-Volkswohlfahrt approached the rector of Frankfurt University at the end of 1936 with a complaint that Meissner had not wanted to make a donation. The conflict was amicably settled by a representative of the rector, but the rector and chancellor sent a report to the Reich Minister for Science, Education and Public Education on December 14, 1936, which culminated in the sentence “… I think it is desirable, Professor Meissner to retire ” . The fact that Ms. Meissner was Jewish played an important role. In fact, Meissner was retired on May 19, 1937, that is, dismissed. The dismissal was due to "administrative simplification".

Emigration to the USA

After difficult negotiations, Meissner found a job at the Worcester Polytechnic Institute in Worcester (Massachusetts) in the USA. On November 15, 1938, the Meissners left Germany involuntarily to lead a life in freedom in the USA. Before leaving, Mrs. Meissner was seriously ill. She did not recover and eventually died in Worcester on July 9, 1939.

At the Polytechnic Institute, Meissner taught undergraduate students , i. In other words, the level of the lectures corresponded roughly to the material that is taught in Germany in the upper secondary level and in the beginning semesters of the course. Research activity was not possible. After the beginning of the Second World War, however, Purdue University in Lafayette (Indiana) became aware of Meissner and appointed him in November 1941. At Purdue University, Meissner continued to research spectroscopic problems with precision methods. In particular, he used spectroscopic measurements of great accuracy to determine a length standard . Here he worked until his death.

Second marriage

In 1942 Meissner married Hanna Hellinger for the second time. Like his first wife, she was Jewish and also fled from Frankfurt to the USA. Since her brother Ernst Hellinger was a professor of mathematics at Frankfurt University, it is likely that the Meissners knew Hanna Hellinger from Frankfurt.

death

In 1959, Meissner set out on a trip to Europe. During the crossing he died of heart failure on April 13, 1959.

Scientific importance

The atomic structure and the quantum mechanical laws that govern the processes in atoms were researched using atomic spectra. The experiments soon showed that the laws of classical physics failed. In this respect, precise experimental data on the spectra of atoms were of great importance for theoretical physicists who were looking for new, previously unknown relationships. During this crucial phase of modern physics in the first half of the 20th century, Meissner worked as one of the leading spectroscopists on this development and provided experimental material on which the theorists could test their ideas. A tool for great experiments was the atomic beam method invented by Meißner and introduced into spectroscopy.

Fonts

Meissner has written 89 scientific papers, mainly articles in scientific journals. His monograph Spectroscopy , de Gruyter, Berlin 1935, (= Göschen Collection. 1091), as well as manual articles for the Handbuch der physical optics (1928) and the Handbuch der Astrophysik (1933 and 1936) should be emphasized .

A full list of publications can be found in the biography of Valentin Wehefritz.

literature

• Kenneth L. Andrew, I. Walerstein: Karl Wilhelm Meissner. In: Journal of the Optical Society of America. 49, 1959, pp. 1024-1025.
• Karl W. Meissner. In: Physics Today. 12, No. 9, 1959, pp. 78-79.
• M. Czerny: Karl Wilhelm Meissner. In: Physical sheets. 15, 1959, p. 420.
• Karl Wilhelm Meissner. In: Proceedings of the Indiana Academy of Science. 69: 1959, 1960, pp. 39-40.
• Jörg Kummer: Karl Wilhelm Meissner. In: K. Bethge, H. Klein (ed.): Physicists and astronomers in Frankfurt. Neuwied 1989, pp. 112-120.
• Helmut Rechenberg:  Meissner, Karl Wilhelm. In: New German Biography (NDB). Volume 16, Duncker & Humblot, Berlin 1990, ISBN 3-428-00197-4 , p. 701 ( digitized version ).
• Valentin Wehefritz: Loyalty overcomes reasons of state. Prof. Dr. phil. Karl Wilhelm Meissner. University Library, Dortmund 2005 (= University in Exile. 6).

Notes and individual references

1. ↑ He died on board a ship in the Atlantic.
2. ↑ The Black Ring. Membership directory. Darmstadt 1930, p. 57.

Web links

• Literature by and about Karl Wilhelm Meissner in the catalog of the German National Library
• Detailed information ( Memento from September 15, 2008 in the Internet Archive )