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==World War I==
==World War I==
Franck enlisted in the [[German Army (German Empire)|German Army]] soon after the outbreak of [[World War I]] in August 1914. In December he was sent to the [[Piccady]] of the [[Western Front (World War I)|Western Front]]. He became a [deputy officer (''[[offizierstellvertreter]]''), and then a lieutenant (''[[leutnant]]'') in 1915.{{sfn|Lemmerich|2011|pp=52-58}} He was awarded the [[Iron Cross]], Second Class, on 30 March 1915,<ref name="Papers">{{cite web |url=https://www.lib.uchicago.edu/e/scrc/findingaids/view.php?eadid=ICU.SPCL.FRANCK |title=Guide to the James Franck Papers 1882-1966 |publisher=[[University of Chicago]] |accessdate=18 June 2015 }}</ref> and the city of Hamburg awarded him the [[Hanseatic Cross]] on 11 January 1916.<ref name="Papers" />
Franck enlisted in the [[German Army (German Empire)|German Army]] soon after the outbreak of [[World War I]] in August 1914. He was


While in hospital with [[pleurisy]], he co-wrote yet another scientific paper with Hertz, and he was appointed an extraordinarius professor in his absence by Frederick William University on 19 September 1916. Sent to the [[Eastern Front (World War I)|Russian front]], he came down with [[dysentery]]. He returned to Berlin, where he joined Hertz, Westphal, [[Hans Geiger]], [[Otto Hahn]] and others at [[Fritz Haber]]'s [[Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry]], working on the development of [[gas masks]].{{sfn|Lemmerich|2011|pp=52-58}} He was awarded the Iron Cross, First Class, on 23 February 1918. He was discharged from the Army on 25 November 1918, soon after the war war ended.<ref name="Papers" />
He lectured and taught until 1918, having reached the position of extraordinarius professor.


==Göttingen==
==Göttingen==

Revision as of 22:25, 17 June 2015

James Franck
Born(1882-08-26)26 August 1882
Hamburg, German Empire
Died21 May 1964(1964-05-21) (aged 81)
Göttingen, West Germany
NationalityGerman
CitizenshipGermany
United States
Alma materUniversity of Heidelberg
University of Berlin
Known forFranck–Condon principle
Franck–Hertz experiment
Franck Report
AwardsIron Cross, 2nd Class (1915)
Hanseatic Cross (1916)
Iron Cross, 1st Class (1918)
Nobel Prize for Physics (1925)
Max Planck Medal (1951)
Rumford Prize (1955)
Scientific career
FieldsPhysics
InstitutionsUniversity of Berlin
University of Göttingen
Johns Hopkins University
University of Chicago
Metallurgical Laboratory
Thesis Über die Beweglichkeit der Ladungsträger der Spitzenentladung  (1906)
Doctoral advisorEmil Gabriel Warburg
Doctoral studentsWilhelm Hanle
Arthur R. von Hippel
Theodore Puck

James Franck (26 August 1882 – 21 May 1964) was a German physicist who won the 1925 Nobel Prize for Physics with Gustav Hertz "for their discovery of the laws governing the impact of an electron upon an atom".[1]

Franck completed his doctorate in 1906 and his habilitation in 1911 at the Frederick William University in Berlin, where he lectured and taught until 1918, having reached the position of professor extraordinarius. He served as a volunteer in the German Army during World War I. He was seriously injured in 1917 in a gas attack and was awarded the Iron Cross 1st Class.

Franck became the Head of the Physics Division of the Kaiser Wilhelm Gesellschaft for Physical Chemistry. In 1920, Franck became professor ordinarius of experimental physics and Director of the Second Institute for Experimental Physics at the University of Göttingen. While there he worked on quantum physics with Max Born, who was Director of the Institute of Theoretical Physics. His work included the Franck–Hertz experiment, an important confirmation of the Bohr model of the atom. He promoted the careers of women in physics, notably Lise Meitner, Hertha Sponer and Hilde Levi.

After the NSDAP came to power in Germany in 1933, Franck resigned his post in protest against the dismissal of fellow academics. He assisted Frederick Lindemann in helping dismissed Jewish scientists find work overseas, before he left Germany in November 1933. After a year at the Niels Bohr Institute in Denmark, he moved to the United States, where he worked at Johns Hopkins University in Baltimore and then the University of Chicago. During this period he became interested in photosynthesis

Franck participated in the Manhattan Project during World War II as Director of the Chemistry Division of the Metallurgical Laboratory. He was also the chairman of the Committee on Political and Social Problems regarding the atomic bomb, which is best known for the compilation of the Franck Report, which recommended that the atomic bombs not be used on the Japanese cities without warning.

Early life

James Franck was born in Hamburg, Germany, on 26 August 1882, the second child and first son of Jacob Franck, a banker, and his wife Rebecca née Nachum Drucker.[2] He had an older sister, Paula, and a younger brother, Robert Bernard.[3] His father was a devout and religious man, while his mother his mother came from a family of rabbis.[2] Franck attended primary school in Hamburg. Starting in 1891 he attended the Wilhelm-Gymnasium, which was then a boys-only school.[3]

Hamburg had no university then, so prospective students had to attend one of the 22 universities elsewhere in Germany. Intending to study law and economics, Franck entered the University of Heidelberg in 1901, as it had a renowned law school.[4] He attended lectures on law, but was far more interested in those on science. While there, he met Max Born, who would become a lifelong friend. With Born's help, he was able to persuade his parents to allow him to switch to studying physics and chemistry.[5] Franck attended mathematics lectures by Leo Königsberger and Georg Cantor, but Heidelberg was not strong on the physical sciences, so he decided to go to the Frederick William University in Berlin.[4]

At Berlin, Franck attended lectures by Max Planck and Emil Warburg.[6] On 28 July 1904 he saved a pair of children from drowning in the Spree River.[6] For his Doctor of Philosophy (Dir. Phil.) under Warburg's supervision,[7] Warburg suggested that he study corona discharges. Franck found this topic too complex, so he changed the focus of his thesis to study the mobility of ions.[8] Entitled Über der Beweglichkeit Ladungsträger der Spitzenethladung,[9] it would subsequently be published in the Annalen der Physik.[10]

With his thesis completed, Franck had to perform his deferred military service. He was called up on 1 October 1906 and joined the 1st Telegraph Battalion. He suffered a minor horse riding accident in December and was discharged as unfit for duty. He took up an assistantship at the de [Physikalische Verein] in Frankfurt in 1907, but did not enjoy it, and soon returned to Frederick William University.[11] At a concert Franck met Ingrid Josephson, a Swedish pianist. They were married in a Swedish ceremony in Göteborg on 23 December 1907. They had two daughters, Dagmar (Daggie), who was born in 1909, and Elisabeth (Lisa), who was born in 1912.[12]

To pursue an academic career in Germany, having a doctorate was not enough; one needed a venia legendi, or habilitation. This could be achieved with either another major thesis or by producing a substantial body of published work. Franck chose the latter route. There were many unsolved problems in physics at the time, and by 1914 he had published 34 articles. He was the sold author of some, but generally preferred working in collaboration with sv [Eva von Bahr], Lise Meitner, Robert Pohl, de [Peter Pringsheim], Robert W. Wood, Arthur Wehnelt or Wilhelm Westphal. His most fruitful collaboration was with Gustav Hertz, with whom he wrote 19 articles. He received his habilitation on 20 May 1911.[13]

Franck–Hertz experiment

In 1914, Franck teamed up with Hertz to perform an experiment to investigate fluorescence. They had designed a vacuum tube for studying energetic electrons that flew through a thin vapor of mercury atoms. They discovered that when an electron collided with a mercury atom it could lose only a specific quantity (4.9 electron volts) of its kinetic energy before flying away. A faster electron doesn't decelerate completely after a collision, but loses precisely the same amount of its kinetic energy. Slower electrons just bounce off mercury atoms without losing any significant speed or kinetic energy.[14][15]

These experimental results provided confirmation of Albert Einstein's photoelectric effect and Planck's relation (E = fh) linking energy (E) and frequency (f) arising from quantisation of energy with Planck's constant (h). But they also provided evidence supporting the model of the atom that had been proposed the previous year by Niels Bohr. Its key feature was that an electron inside an atom occupies one of the atom's "quantum energy levels". Before a collision, an electron inside the mercury atom occupies its lowest available energy level. After the collision, the electron inside occupies a higher energy level with 4.9 electron volts (eV) more energy. This means that the electron is more loosely bound to the mercury atom. There were no intermediate levels or possibilities.[14][16]

In a second paper presented in May 1914, Franck and Hertz reported on the light emission by the mercury atoms that had absorbed energy from collisions. They showed that the wavelength of this ultraviolet light corresponded exactly to the 4.9 eV of energy that the flying electron had lost; for visible light, different wavelengths correspond to different colours. The relationship of energy and wavelength had also been predicted by Bohr.[14][17] On 10 December 1926, Franck and Hertz were awarded the 1925 Nobel Prize in Physics "for their discovery of the laws governing the impact of an electron upon an atom.".[1] In his Nobel lecture, Franck admitted that it was "completely incomprehensible that we had failed to recognise the fundamental significance of Bohr’s theory, so much so, that we never even mentioned it once in the relevant paper."[18]

World War I

Franck enlisted in the German Army soon after the outbreak of World War I in August 1914. In December he was sent to the Piccady of the Western Front. He became a [deputy officer (offizierstellvertreter), and then a lieutenant (leutnant) in 1915.[19] He was awarded the Iron Cross, Second Class, on 30 March 1915,[20] and the city of Hamburg awarded him the Hanseatic Cross on 11 January 1916.[20]

While in hospital with pleurisy, he co-wrote yet another scientific paper with Hertz, and he was appointed an extraordinarius professor in his absence by Frederick William University on 19 September 1916. Sent to the Russian front, he came down with dysentery. He returned to Berlin, where he joined Hertz, Westphal, Hans Geiger, Otto Hahn and others at Fritz Haber's Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry, working on the development of gas masks.[19] He was awarded the Iron Cross, First Class, on 23 February 1918. He was discharged from the Army on 25 November 1918, soon after the war war ended.[20]

Göttingen

World War II

When Nazi Germany invaded Denmark in World War II, the Hungarian chemist George de Hevesy dissolved the gold Nobel Prizes of Max von Laue and James Franck in aqua regia to prevent the Nazis from stealing them. He placed the resulting solution on a shelf in his laboratory at the Niels Bohr Institute. After the war, he returned to find the solution undisturbed and precipitated the gold out of the acid. The Nobel Society then recast the Nobel Prizes using the original gold.[21]

He was also the chairman of the Committee on Political and Social Problems regarding the atomic bomb; the committee consisted of himself and other scientists at the Met Lab, including Donald J. Hughes, J. J. Nickson, Eugene Rabinowitch, Glenn T. Seaborg, J. C. Stearns and Leó Szilárd. The committee is best known for the compilation of the Franck Report, finished on 11 June 1945, which recommended not to use the atomic bombs on the Japanese cities, based on the problems resulting from such a military application.

In 1946 Franck married Hertha Sponer, his former assistant in Göttingen. He died suddenly in 1964 while visiting Göttingen.

Later life

On his religious views, Franck commented that science was his God and nature was his religion.[22]

Honours and awards

Notes

  1. ^ a b "The Nobel Prize in Physics 1925". The Nobel Foundation. Retrieved 16 June 2015.
  2. ^ a b Rice & Jortner 2010, p. 4.
  3. ^ a b Lemmerich 2011, pp. 8–11.
  4. ^ a b Lemmerich 2011, pp. 12–15.
  5. ^ Kuhn 1965, pp. 53–54.
  6. ^ a b Lemmerich 2011, pp. 16–17.
  7. ^ Rice & Jortner 2010, p. 5.
  8. ^ Kuhn 1965, pp. 54–55.
  9. ^ Lemmerich 2011, p. 331.
  10. ^ Franck, J. (1906). "Über die Beweglichkeit der Ladungsträger der Spitzenentladung". Annalen der Physik (in German). 326 (15): 972–1000. doi:10.1002/andp.19063261508. ISSN 1521-3889.
  11. ^ Lemmerich 2011, pp. 24–26.
  12. ^ Lemmerich 2011, pp. 34–35.
  13. ^ Lemmerich 2011, pp. 24–31.
  14. ^ a b c Kuhn 1965, pp. 55–56.
  15. ^ Franck, J.; Hertz, G. (1914). "Über Zusammenstöße zwischen Elektronen und Molekülen des Quecksilberdampfes und die Ionisierungsspannung desselben". Verhandlungen der Deutschen Physikalischen Gesellschaft (in German). 16: 457–467. {{cite journal}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)
  16. ^ Hon, Giora (1989). "Franck and Hertz versus Townsend: A Study of Two Types of Experimental Error". Historical Studies in the Physical and Biological Sciences. 20 (1): 79–106. JSTOR 27757636.
  17. ^ Franck, J.; Hertz, G. (1914). "Über die Erregung der Quecksilberresonanzlinie 253,6 μμ durch Elektronenstöße". Verhandlungen der Deutschen Physikalischen Gesellschaft (in German). 16: 512–517. {{cite journal}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)
  18. ^ "Transformations of Kinetic Energy of Free Electrons into Excitation Energy of Atoms by Impacts Nobel Lecture" (PDF). The Nobel Foundation. 11 December 1926. Retrieved 16 June 2015.
  19. ^ a b Lemmerich 2011, pp. 52–58.
  20. ^ a b c "Guide to the James Franck Papers 1882-1966". University of Chicago. Retrieved 18 June 2015.
  21. ^ "Adventures in radioisotope research", George Hevesy
  22. ^ Nachmansohn 1979, p. 62

References

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