Heinrich Gerhard Kuhn

A graduate of the University of Göttingen, where he studied for his doctorate under the direction of James Franck, winner of the 1925 Nobel Prize for Physics, he left Germany after the Nazi Party came to power there in 1933, and moved to Britain, where relatives had settled, becoming a British subject in 1939.

At the invitation of Frederick Alexander Lindemann, he worked for Imperial Chemical Industries at the Clarendon Laboratory in Oxford, where he studied hyperfine structure.

Franck had recently published a theory of electron motion and diatomic molecules, and at his suggestion Kuhn studied the absorption spectra of chlorine (Cl2) and bromine (Br2).

His results confirmed the Franck–Condon principle and formed his 1926 doctoral thesis on Absorptionspektrum und Dissoziationswarmen von Halogenmolekül (Absorption spectra and dissociation warming of halogen molecules).

They were welcomed by his relatives, the Henschels, and Kuhn received a grant of £400 per annum from ICI, initially for two years, but it was extended to three, and then six.

They attended Dragon School and St Edward's, and entered Balliol College, Oxford, where they earned doctorates.

At the Clarendon laboratory, Jackson and Kuhn studied the hyperfine structure and Zeeman effects of the light elements such a lithium, sodium and potassium.

[1] In 1940, Kuhn joined a team led by Francis Simon that also included Henry Shull Arms, Nicholas Kurti, and Otto Frisch working on the British nuclear weapons project, known as Tube Alloys.

[1][3] Jackson left Britain for tax purposes after the war, but Kuhn remained at Oxford, where he continued his research into atomic spectra with G.W.