In 1950–1951,James Rainwater andAage Bohr had developed models of theatomic nucleus which began to take into account the behaviour of the individualnucleons. These models, which moved beyond the simplerliquid drop treatment of the nucleus as having effectively no internal structure, were the first models which could explain a number of nuclear properties, including the non-spherical distribution of charge in certain nuclei. Mottelson worked with Aage Bohr to compare the theoretical models with experimental data. In 1952–1953, Bohr and Mottelson published a series of papers demonstrating close agreement between theory and experiment, for example showing that the energy levels of certain nuclei could be described by a rotation spectrum.[6][7][8][9] This work stimulated new theoretical and experimental studies.
In the summer of 1957,David Pines visited Copenhagen, and introduced Bohr and Mottelson to the pairing effect developed in theories ofsuperconductivity, which inspired them to introduce a similar pairing effect to explain the differences in the energy levels betweeneven and odd atomic nuclei.[10]
Rainwater, Bohr and Mottelson were jointly awarded the 1975 Nobel Prize in Physics "for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of thestructure of the atomic nucleus based on this connection".[11]
Bohr and Mottelson continued to work together, publishing a two-volumemonograph,Nuclear Structure. The first volume,Single-Particle Motion, appeared in 1969,[12][13] and the second volume,Nuclear Deformations, in 1975.[14][15]
Mottelson was adual citizen, as he held bothDanish andAmerican passports. He lived inCopenhagen. Mottelson was married to Nancy Jane Reno from 1948 until her death in 1975, and they had two sons and one daughter. Mottelson then married Britta Marger Siegumfeldt in 1983.[22]
^Bohr, A.; Mottelson, B. R.; Pines, D. (15 May 1958). "Possible Analogy between the Excitation Spectra of Nuclei and Those of the Superconducting Metallic State".Physical Review.110 (4). American Physical Society (APS):936–938.Bibcode:1958PhRv..110..936B.doi:10.1103/physrev.110.936.ISSN0031-899X.
