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No. 69: May-Jun 1990

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Krypton-cluster magic numbers

Krypton atoms cluster together in stable clumps
Krypton atoms cluster together in stable clumps of 13, 55, 147, 309, 561,... atoms.
Ordinarily, krypton, being a noble gas, does not enter into any combinations with other atoms - even other krypton atoms. However, P. Lethbridge and T. Stace, at the University of Sussex, have coaxed krypton atoms to cluster together in large, crystal-like clumps with icosohedral symmetry; that is each clump possesses 20 regular faces. The coaxing occurs when gaseous krypton trickles into a vacuum chamber through a hole only 200 micrometers in diameter. The expansion of the gas cools it so that when krypton atmos collide, relative velocities are low, and the weak Van de Waals forces between the atoms are sufficient to hold the clumps together.

So far, clumps of 147 and 309 atoms have been detected with a mass spectrograph. One theory of atomic "pack ing" predicts clumps should have "magic numbers" of 13, 55, 147, 309, 561, 923 .... So far, the "magic" has been working!

(Baggott, Jim; "Krypton Atoms Cling Together in 'Shells,'" New Scientist, p. 31, March 3, 1990.)

Comment. One would anticipate that the smaller clumps of 13 and 55 atoms would be easier to assemble.

From Science Frontiers #69, MAY-JUN 1990. 1990-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:

Quotes

  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987