London: Physicists have finally created
the nuclear "missing link" on the list of observed elements --
the superheavy element 117, which is made of atoms containing
117 protons that is roughly 40 per cent heavier than lead.
A team from the US and Russia produced the elusive
element 117 by fusing together atoms of calcium and another
rare, heavy element known as berkelium, filling in the final
gap on the list of observed elements up to 118.
Like all superheavy atoms, element 117 is unstable,
lasting only fractions of a second before self-destructing in
a cascade of lighter elements and particles.
After smashing calcium atoms into a target of
berkelium in a particle accelerator at the Joint Institute for
Nuclear Research in Dubna, Russia, the team deduced fleeting
existence of element 117 by studying the daughter particles
emitted as the atom decayed.
Despite the atom`s short lifetime, element 117 lives
longer than many lighter elements.
The discovery confirms theories that predict that
117 and its recently synthesised cousins, elements 116 and
118, exist in an island of stability on the periodic table.
Only synthesising increasingly heavy elements will show just
how far the stable region extends up the list of elements.
While there is no known practical application for
such short-lived atoms, the synthesis of superheavy elements
is vital for testing models that explain how the neutrons and
protons that make up all the elements bind together, according
to the physicists.
Such models in turn help explain the relative
proportion of more common elements in the universe, as well as
offering predictions of other exotic atoms that may be stable
enough occur naturally on Earth or in meteorites.
The findings are to appear in the `Physical Review
Letters` journal.
PTI
