Scientists may be adding a new element to the periodic table, but don’t
expect to see it anytime soon: created in a laboratory, it exists for
less than a second.
The new superheavy chemical element has 115 protons and would fill a gap
in the periodic table, taking its place between the two elements, 114
and 116, which were added just last year.
The newcomer, as yet unnamed, was first discovered a decade ago by
Russian and American scientists, but the official organizations of
chemists and physicists that act as gatekeepers for the periodic table
wanted another laboratory to repeat the experiment before they would
officially add it.
A Swedish university announced Tuesday that that had finally happened.
The new work, led by physicists at Lund University in Sweden and
performed at an accelerator in Darmstadt, Germany, duplicated the
earlier experiment and observed the similar patterns of debris. The new
findings will be published Thursday in the journal Physical Review
Letters.
“Everything is perfect,” said Krzysztof Rykaczewski, a scientist at Oak
Ridge National Laboratory in Tennessee who was a member of the
confirmation team.
The experiment also provided additional confirmation of earlier claims
for element 113, which also has not yet been added to the periodic
table, Dr. Rykaczewski said. In the first decay, element 115 turned into
element 113 while emitting a chunk known as an alpha particle.
The Russian-American team had already replicated its own results, but,
“it’s always better when someone else does it,” Dr. Rykaczewski said.
To create the element, calcium nuclei were fired into a target
containing americium atoms. Occasionally, a calcium and an americium
merged together, creating a new atom with 115 protons in its nucleus.
Then, in less than a second, it fell apart. The researchers deduced its
existence from the pieces of debris.
In addition, for the first time, the researchers observed an X-ray
“fingerprint” emitted during the decay, which provided more direct
evidence that the initial atom contained 115 protons.
Dirk Rudolph, a professor of nuclear physics at Lund University, said he
was “most satisfied” that the team had created the element. “Mother
Nature has not been as kind as she could have been,” he said.
The number of observed X-rays — just two — was too few to be definitive,
but “we obviously show the feasibility of such experiments,” he said.
If the new data proves convincing, the Russian and American scientists
who made the original discovery would be given the opportunity to name
the element, a process that would take months.
Just last year, the overseers of the periodic table acceded to the
addition of elements 114 and 116 as flerovium and livermorium, more than
a decade after they were first made. The elements 117 and 118 have also
been claimed, but not yet confirmed.
The study of superheavy atoms — which are unstable chemical elements
with atomic numbers greater than 92 — help scientists better understand
the basic forces that hold matter together.
No comments:
Post a Comment