update.527 (fwd)

[Jim Choate]

---------- Forwarded message ----------
Date: Fri, 23 Feb 2001 13:43:41 -0500 (EST)
From: AIP listserver <physnews at aip.org>
To: physnews-mailing at aip.org
Subject: update.527

PHYSICS NEWS UPDATE                         
The American Institute of Physics Bulletin of Physics News
Number 527  February 23, 2001   by Phillip F. Schewe, Ben Stein,
and James Riordon

SILICON CAGE CLUSTERS: BETTER THAN BUCKYBALLS?
The discovery of carbon fullerenes (Update 2) caught the
imagination of scientists and the public alike as researchers raced
to find applications for the tiny spheres commonly called
buckyballs. Now researchers at the Joint Center for Atomic
Research in Japan have managed to create similar arrangements of
silicon atoms, a feat previously thought impossible owing to
silicon's chemical nature. Potential applications of the silicon
assemblies range from components in quantum computers to
chemical catalysts to new superconducting compounds. Silicon is,
of course, a vital material for the vast semiconductor industry and
one of the most studied elements in all of science.  Therefore this
new discovery might lead to applications that could match or even
exceed those expected for carbon fullerenes.  Unlike carbon atoms,
pure silicon cannot form stable, closed configurations. The new
research, however, reveals that silicon can gather around a central
metal atom and settle into basket-like arrangements called silicon
cage clusters. One particularly low energy, and therefore stable,
configuration consists of twelve silicon atoms forming a regular,
hexagonal cage that surrounds a tungsten atom (see figure at
http://www.aip.org/physnews/graphics).  Because the choice of a
central metal atom affects the chemical behavior of cage clusters,
scientists should be able to tailor the clusters to create novel
nanodevices and catalysts. The researchers (Hidefumi Hiura, h-
hiura at bq.jp.nec.com, 011-81-298-50-2615) note in particular that
clusters efficiently isolate their guest metal atoms from the
surrounding environment, a characteristic that could permit a
cluster to act as a robust qubit in a quantum computer by storing a
single bit of information in the spin state of the enclosed metal
atom. (H. Hiura et al, Physical Review Letters, 26 February 2001.)

UNTYING THE KNOT.  Dealing with shoelaces is for most of us
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PERMIAN CATASTROPHE COMET?  A trace of indium in
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                                           George Zebrowski

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