Rudolf Ladenburg

Rudolf Ladenburg
Ladenburg in 1937
Born	Rudolf Walter Ladenburg (1882-06-06)6 June 1882 Kiel, Kingdom of Prussia, German Empire
Died	6 April 1952(1952-04-06) (aged 69) Princeton, New Jersey, U.S.
Alma mater	University of Munich (Dr. phil.)
Title	Cyrus Fogg Brackett Professor of Physics (1930–50)
Spouse	Else Uhthoff ​ (m. 1911)​
Children	3
Father	Albert Ladenburg
Scientific career
Fields	Physics
Institutions	University of Breslau (1906–24) University of Berlin (1924–30) Princeton University (1930–50)
Thesis	Über die innere Reibung zäher Flüssigkeiten und ihre Abhängigkeit vom Druck (1906)
Doctoral advisor	Wilhelm Röntgen
Doctoral students	Henry Barschall (1940)[1] John Winckler (1946)[1]

Rudolf Walter Ladenburg (6 June 1882 – 6 April 1952) was a German physicist. When the wave of German emigration began in 1933, he was the principal coordinator for job placement of exiled physicists in the United States. Albert Einstein gave the eulogy at Rudolf's funeral.

Biography

Rudolf Walter Ladenburg was born on 6 June 1882 in Kiel, Germany, the son of Jewish chemist Albert Ladenburg and Margarete Pringsheim.^[2] He was a non-practicing Jew and an atheist.^[3]

From 1900 to 1906, Ladenburg studied at the universities of Heidelberg, Breslau, and Munich. In 1906, he received his Ph.D. under Wilhelm Röntgen at Munich.^[4]

In 1911, Ladenburg married Else Uhthoff, with whom he had three children; Margarethe, Kurt, and Eva.

After completing his habilitation, Ladenburg became a Privatdozent at Breslau, and in 1909 an ausserordentlicher Professor. In 1924, he took an appointment at the University of Berlin, along with becoming a scientific member of the Kaiser Wilhelm Institute of Physical Chemistry and Electrochemistry of the Kaiser Wilhelm Society in Berlin.^[5]

Ladenburg went to the United States in 1930,^[6] when he was appointed to the Cyrus Fogg Brackett Chair of Physics at Princeton University. When the emigration wave from Germany began in April 1933, he was the principal coordinator for the employment of exiled physicists in the United States. He retired from Princeton in 1950.^[7][8]

Ladenburg died on 6 April 1952 in Princeton, New Jersey, at the age of 69.

Articles

• Rudolf Ladenburg and Stanislaw Loria Nature, Anomalous Dispersion of Luminous Hydrogen Volume 79, 7-7 (5 November 1908)
• Rudolf Ladenburg Die quantentheoretische Bedeutung der Zahl der Dispersionelektronen, Z. Phys. Volume 4, Number 4, 451-468 (1921). Received on 8 February 1921. Institutional affiliation: Breslau, Physikal. Institut der Universität. English translation: The quantum-theoretical number of dispersion electrons in B. L. van der Waerden Sources of Quantum Mechanics (Dover, 1968) pp. 139 – 157.
• R. Ladenburg and F. Reiche Dispersionsgesetz und Bohrsche Atomtheorie, Die Naturwissenschaften , Volume 12, Issue 33, pp. 672–673 (1924)
• Hans Kopfermann and Rudolf Ladenburg Elektrooptische Untersuchungen am Natriumdampf. (Anomale elektrische Doppelbrechung; Starkeffekt an der Resonanzstrahlung), Annalen der Physik, Volume 383, Issue 23, pp. 659–679 (1925)
• Hans Kopfermann and Rudolf Ladenburg Untersuchungen über die anomale Dispersion angeregter Gase II Teil. Anomale Dispersion in angeregtem Neon Einfluß von Strom und Druck, Bildung und Vernichtung angeregter Atome, Zeitschrift für Physik Volume 48, Numbers 1-2, pp. 26–50 (January, 1928). Received 17 December 1927. Institutional affiliation: Kaiser-Wilhelm Institut für physikalische Chemie und Elektrochemie, Berlin-Dahlem.
• H. Kopfermann and R. Ladenburg Experimental Proof of ‘Negative Dispersion’, Nature Volume 122, 438-439 (22 September 1928)
• R. Ladenburg and S. Levy Untersuchungen über die anomale Dispersion angeregter Gase VI. Teil: Kontrollversuche für den Nachweis der negativen Dispersion: Absorption, anomale Dispersion, Intensitätsverteilung und Intensität verschiedener Neonlinien Zeitschrift für Physik Volume 65, Numbers 3-4. pp. 189–206 (March, 1930). Received 12 August 1930. Institutional affiliation: Kaiser-Wilhelm Institut für physikalische Chemie und Elektrochemie, Berlin-Dahlem.
• Rudolf Ladenburg Dispersion in Electrically Excited Gases Rev. Mod. Phys. Volume 5, 243 - 256 (1933). The author was cited as being at Princeton University.
• Rudolf W. Ladenburg Light absorption and distribution of atmospheric ozone, Journal of the Optical Society of America, Volume 25, Issue 9, p. 259 (1935)
• Max Born, R. Fürth, and Rudolf Ladenburg Long Duration of the Balmer Spectrum in Hydrogen, Nature Volume 157, pp. 159–159 (9 February 1946). Institutional affiliations: Born and Fürth were identified as being in the Department of Mathematical Physics, The University, Edinburgh, and Ladenburg was identified as being in the Palmer Physical Laboratory, Princeton University, Princeton, New Jersey.

Books

• Rudolf Walter Ladenburg Planck's elementares Wirkungsquantum und die Methoden zu seiner Messung (Hirzel, 1921)

Notes

1. "Rudolf Ladenburg - Physics Tree". academictree.org. Retrieved 15 September 2025.
2. Hentschel and Hentschel, 1996, 227n22.
3. Albert Ladenburg, Lebenserinnerungen (Breslau: Trewendt & Granier, 1912), pp. 51-52. Neither Willstätter nor Ladenburg were practicing Jews, and both were fully assimilated Germans. Ladenburg was in fact an atheist; for reasons that he does not explain, he finally underwent baptism in 1891.
4. Hentschel and Hentschel, 1996, Appendix F; see the entry for Ladenburg.
5. Hentschel and Hentschel, 1996, Appendix F; see the entry for Ladenburg.
6. "New York, New York Passenger and Crew Lists, 1909, 1925-1957," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:24FB-ZC6 : 2 October 2015), Rudolf Ladenburg, 1930; citing Immigration, New York, New York, United States, NARA microfilm publication T715 (Washington, D.C.: National Archives and Records Administration, n.d.).
7. Hentschel and Hentschel, 1996, p. 227.
8. Hentschel and Hentschel, 1996, Appendix F; see the entry for Ladenburg.

Further reading

• Hentschel, Klaus (Editor) and Ann M. Hentschel (Editorial Assistant and Translator) Physics and National Socialism: An Anthology of Primary Sources (Birkhäuser, 1996)
• Glaser, Ludwig Juden in der Physik: Jüdische Physik, Zeitschrift für die gesamte Naturwissenschaften Volume 5, Number 8, 272-272 (November 1939). Translated and published as Document 77 Ludwig Glaser: Jews in Physics: Jewish Physics [November 1939], in Hentschel, Klaus (Editor) and Ann M. Hentschel (Editorial Assistant and Translator) Physics and National Socialism: An Anthology of Primary Sources (Birkhäuser, 1996) pp. 223–234.