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Nanoworld sets the Limit to "Small"
Scientist at University
of Arizona stating 25 Nanometer as the limit to which
object can be shrinked. This is mainly due to existence
of Vander waal's force existing between atom and molecules
of any substance.
Researchers Perreault
and Cronin used Atom Interferometer which they bought
from MIT to conduct experiment for setting limit for
the small world in nanotechnology. Perreault and Cronin
found that atoms closer than 25 nanometers to a surface
are very strongly attracted to the surface because
of the van der Waals interaction, so strongly that
the atoms are accelerated with the force of a million
g's.
A "g" is a
term for acceleration due to gravity. One g is an
everyday experience -- it's the force a person feels
from Earth's gravity. A roller coaster rider might
feel 3 to 4 g's for brief moments during a ride. Fighter
pilots can experience accelerations of up to 8 g for
brief periods during tactical maneuvers, but can black
out if subjected to 4 to 6 g's for more than a few
seconds.
"We might say that
when an atom is between 10 and 20 nanometers from
a surface, it gets sucked toward the surface with
a force a million times its weight," Cronin said.
"And when it gets closer, it gets pulled even
harder."
"Our research provides
the first direct experimental evidence that a surface
25 nanometers away (25 billionths of a meter) causes
a shift in the atom wave crests," Perreault said.
"It shows that the van der Waals interaction
may be a small scale force, but it's a big deal for
atoms."
Nanotechnology research
aims to build much smaller transistors and motors,
for example, than currently exist. Atom optics research
aims to exploit the wave behavior of atoms in ways
that will make more precise gyroscopes for navigation,
gravity gradiometers for subterranean mapping and
other field sensors.
"I think the impact
of our work stems from the intersection of the fields
of atom optics and nanotechnology," Perreault
said. "It answers the question of how far you
can miniaturize an atom optics device - for example,
a device that guides atoms on a chip to form a very
tiny
interferometer - before this nano-interaction disrupts
operations."
Vander Waal's Force
These are very weak attractive forces that exist between
the atoms and molecules of all the substances. These
are short range forces and arises due to molecular
dipoles (The product of either charge in an electric
dipole with the distance separating them).
Original News can be
found here
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