Editor's Summary
16 June 2005
Silicon: the question is 42
Dramatic advances are being made in nuclear structure physics because of the availability of facilities producing beams of exotic radioisotopes. Of these, silicon-42 is of particular interest for study of the effects of packing extra neutrons into a nucleus. Neutrons and protons in atomic nuclei are arranged in a series of energy levels or 'shells'. When a shell has a full quota of particles, the nucleus is particularly stable: the 'magic numbers' for stability are 2, 8, 20, 28, 50, 82 and 126. Silicon-42 owes its existence to its 28 neutrons, but is still a short-lived atom. This short lifetime has been explained as a consequence of strong deformation but this is contradicted in a new study that suggests that silicon-42 is almost spherical.
News and Views: Nuclear physics: Elusive magic numbers
Gaps in nuclear levels, which cause nuclei with 'magic' numbers of protons or neutrons to be especially stable, seem to be different for nuclei with an excess of neutrons. But are all magic numbers aberrant in exotic species?
Robert V. F. Janssens
doi: 10.1038/435897a
Letter: 'Magic' nucleus 42Si
J. Fridmann, I. Wiedenhöver, A. Gade, L. T. Baby, D. Bazin, B. A. Brown, C. M. Campbell, J. M. Cook, P. D. Cottle, E. Diffenderfer, D.-C. Dinca, T. Glasmacher, P. G. Hansen, K. W. Kemper, J. L. Lecouey, W. F. Mueller, H. Olliver, E. Rodriguez-Vieitez, J. R. Terry, J. A. Tostevin and K. Yoneda
doi: 10.1038/nature03619
