Physics Nobel Prize 1975

Nobel prize winners, left to right, A. Bohr, B. Mottelson and J. Rainwater.

0. Kofoed-Hansen (Photos Keystone Press, Photopress)

Before 1949 every physicist knew that mooted, it was a major breakthrough from 1943-45. From December 1943 the atomic nucleus does not rotate. in thinking about the nucleus and he was actually in the USA. Back in The reasoning behind this erroneous opened a whole new field of research Denmark after the war, he obtained belief came from the following argu• in nuclear physics. This work has for his Ph. D. in 1954 for work on rota• ments. A quantum-mechanical rotator years been guided by the inspiration tional states in atomic nuclei. His with the moment of inertia J can take of Bohr and Mottelson. thesis was thus based on the work for up various energy levels with rota• An entire industry of nuclear which he has now been recognized at tional energies equal to h2(l + 1)| research thus began with Rainwater's the very highest level. He is Professor /8TC2J, where h is Planck's constant brief contribution to Physical Review at the Niels Bohr Institute of the ^nd I is the spin. As an example, I may in 1950 entitled 'Nuclear energy level University of Copenhagen and a nave values 0, 2, 4, ... etc. If the argument for a spheroidal nuclear member of the CERN Scientific Policy nucleus is considered as a rigid body, model'. Today a fair-sized library is Committee. then the moment of inertia J is very needed in order to contain all the Ben Mottelson was born in the USA large and the rotational energies papers written on deformed nuclei and in 1926 and has, for many years, become correspondingly very small. on the related experimental results. been a naturalized Dane. I know little Consequently states of high spin and Some of the major results concern about his education and pre-Danish low excitation energy would exist and rotational states. Coulomb excitation, background. He seems studiously isomers would thus decay rapidly intensity rules in decay branches, the to avoid filling in the forms which via these states. Since isomers do in nuclear physics equivalent of super• the innumerable 'Who's Who' com- fact exist it seemed that the nucleus conductivity, vibrational states, the pendiums have sent to him. The sub• does not rotate. Nilsson model, models of fission, etc. sequent write-ups are all very laconic In 1950, J. Rainwater pointed out Bohr, Mottelson and Rainwater and most frequently list him simply as that the observed large nuclear qua• received the 1975 Nobel prize in a Professor at NORDITA without druple moments could be accounted physics for this work. All three remain further comment. for by unifying the Mayer-Jensen active in physics and have repeatedly James Rainwater was born in the nuclear shell model and the Niels opened new doors. Bohr and Mottel• USA in 1921. He studied at the Bohr liquid drop model into a picture son have stayed mainly in nuclear California Institute of Technology and which has since been elaborated con• physics while Rainwater has moved later at Columbia University, New siderably by A. Bohr and B. Mottelson. to higher energies. Needless to say, York (Ph. D. in 1946) where he has jsing these ideas, large quadrupole they are all three highly respected felt at home ever since. He has major moments can be combined with small members of the scientific community. research achievements in many other effective moments of inertia and both Aage Bohr was born in Denmark fields. He invented and applied low lying isomer states and higher in 1922. At the time when he would (together with W. Havens) the time lying rotational states can occur. normally have been concentrating on of flight method for neutron spectro• In the terms of A. Bohr, one has a his studies, life in Copenhagen had its scopy, he is the constructor of the deformation that travels as a surface difficulties and he and his father, Nevis synchro-cyclotron, he introduc• wave. This point nowadays sounds Niels Bohr (Nobel Laureat 1922), ed the field of mesic atoms and has a trivial but at the time it was first escaped to join a British research team long list of experiments to his name.

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