Werner Kuhn (physical chemist)

from Wikipedia, the free encyclopedia

Werner Kuhn (born February 6, 1899 in Maur am Greifensee ; † August 27, 1963 in Basel ) was a Swiss physical chemist .

Life and scientific work

Werner Kuhn studied chemistry at the ETH Zurich from 1917 and received his diploma as an engineer - chemist in 1921 . In 1923 he received his doctorate with a thesis on the photochemical decomposition of ammonia. He then worked for two years as a Rockefeller Fellow in Copenhagen under Niels Bohr investigating the absorption bands of molecules. In 1927 Werner Kuhn completed his habilitation at the University of Zurich with a thesis on the strength of anomalous dispersion in vapors of potassium, thallium and cadmium. From 1927 to 1930 he worked with Karl Freudenberg at Heidelberg University with optically active substances. The focus here was the photochemical production of optically active compounds from optically inactive substances. For a few months he moved to Ernest Rutherford's nuclear physics laboratory in Cambridge , where he dealt with the emission and absorption of gamma quanta and thus carried out studies similar to those of Rudolf Mössbauer , whose work later led to the Mössbauer effect .

From 1930 to 1936 Werner Kuhn was Associate Professor at the Institute for Physical Chemistry in Karlsruhe . During this time, the focus of his research was the behavior of thread molecules in solutions, in particular on the coiling and uncoiling of polymers in a flow. In 1936 he received a full professorship at the University of Kiel and carried out further experiments on the photochemical generation of optically active substances, but also in particular on the photochemical isotope separation . Important for today isotope separation ultracentrifugation method also consider supplementing the centrifugal effect in were gas centrifuge by the counterflow principle , which already by him previously for the distillation , for in a thin tube (hairpin countercurrent principle) for the purpose of isotope separation (. B . Extraction of heavy water ) was further developed. This multiplication principle based on the Kuhn-Martin process is now the basis in industrial separation systems for uranium enrichment .

In 1939 Werner Kuhn accepted an offer at the University of Basel . During this time, further work was done on optical activity, a theory about the interior of the earth, whereby he assumed the flow behavior of high-polymer materials and an artificial muscle model based on a polyacrylic acid gel. In a thesis, the tension in polymer networks was explained based on the birefringence occurring during their deformation, thus introducing the principle of entropy elasticity .

One of his doctoral students in Basel was Hans Kuhn , who was not closely related to him and who received his doctorate in 1944.

In 1938 Kuhn published a textbook on physical chemistry. In 1955 he held the office of Rector of the University of Basel. During his tenure, Niels Bohr received an honorary doctorate in Basel. In 1956 he was elected a member of the Leopoldina . In 1961, Kuhn was awarded the Marcel Benoist Prize . Also in 1961 he was elected to the American Academy of Arts and Sciences . Since 1947 he was a corresponding member of the Heidelberg Academy of Sciences .

literature

Web links

Individual evidence

  1. ↑ W. Kuhn and F. Grün, Relationships between elastic constants and expansion birefringence of highly elastic substances Kolloidzeitschrift, Vol. 101 (1942), (3) pp. 248–271 doi : 10.1007 / BF01793684 .
personal data
SURNAME Kuhn, Werner
BRIEF DESCRIPTION Swiss physical chemist
DATE OF BIRTH February 6, 1899
PLACE OF BIRTH Maur
DATE OF DEATH August 27, 1963
Place of death Basel