Discovery of new superheavy elements 113 and
two newest superheavy elements, 113 and 115, were recently discovered
through a collaborative effort between researchers from the Joint
Institute for Nuclear Research (JINR) in Russia and scientists
from Livermore’s Glenn T. Seaborg Institute and the Chemistry
and Materials Science Directorate.
experiments conducted between July 14 and August 10, 2003, at
the JINR U400 cyclotron with the Dubna gas-filled separator,
the team of scientists observed atomic decay patterns, or chains,
that confirm the existence of elements 113 and 115. In these
decay chains, element 113 is produced via the alpha decay of
element 115. Energy Secretary Spencer Abraham says, “These
elemental discoveries underscore both the value of federally
supported basic research and the benefit of unfettered international
experiments produced four atoms each of element 113 and element
115 through the fusion reaction of calcium-48 nuclei impinging
on an americium-243 target. The team observed three similar decay
chains consisting of five consecutive alpha decays, which combined
took less than 30 seconds and terminated in a spontaneous fission
of an element-105 (dubnium) isotope with a very long half-life
(16 hours). Results from the team’s research are featured
in the February 2, 2004, issue of Physical Review C.
Joshua Patin, Livermore’s primary data analyst on the team,
says the three similar decay patterns were a “positive identifier
that something good had been seen, because the long decay chains
just don’t happen that often.” Scientists at Livermore
and JINR independently verified the data.
Contact: Joshua Patin (925) 422-6341
Details of water-to-air interface revealed
the Laboratory’s terascale computers, Livermore scientists
have revealed details of the reactive states and faster relaxation
of molecules at the interface of water and air. Christopher Mundy
and I-Feng Kuo created the first ab initio simulations of
a stable liquid–air interface. Ab initio simulations present
an unbiased representation of water in different environments and
are ideal for explaining surface conditions.
data analysis shows a faster relaxation of water molecules at the
interface and reveals that the surface contains far more reactive
states than the bulk water. “These simulations serve as an
important step toward the use of terascale resources to produce
simulations of water in complex environments,” says Mundy.
addition, the models successfully captured surface phenomena of
water recently observed experimentally by Professor Richard Saykally’s
group at the University of California at Berkeley. A paper describing
this work appeared in the January 30, 2004, issue of Science.
Contact: Christopher Mundy (925) 422-9571
Scientists unveil melting point of iron at
physicists Jeffrey Nguyen and Neil Holmes have discovered that
iron at conditions comparable to Earth’s core melts at a
pressure of 225 gigapascals and a temperature of about 5,100 kelvins.
Determining the melting point of iron is essential to determining
the temperatures at core boundaries and the crystal structure of
Earth’s solid inner core. To date, the properties of iron
at high pressure have been investigated experimentally through
both laser-heated, diamond-anvil cell experiments and shock-compression
techniques as well as through theoretical calculations.
those techniques have not produced a consensus on the melt line
or the high-pressure, high-temperature phase of iron in the inner
core. Using the Laboratory’s two-stage gas gun, the researchers
demonstrated that a shocked sample of iron crosses the melt line
at a pressure between that of the core–mantle boundary and
the pressure of the inner–outer core boundary.
determining the melting point of iron, we can estimate the temperature
at the core boundaries,” Nguyen said. “These data provide
us with more information to study the temperature of Earth’s
core.” Nguyen and Holmes’s results appeared in the
January 22, 2004, issue of Nature.
Contact: Jeffrey Nguyen (925)