Physicists Observe Electron Ejected from Atom for First Time

Wright-Patterson Air Force Base ^ | September 28, 2010 | Maria Callier

[decimon]

9/24/2010 - ARLINGTON, Va. -- Air Force Office of Scientific Research-supported physicists at the University of California, Berkeley in collaboration with researchers from the Max Planck Institute of Quantum Optics and the U.S. Department of Energy's Lawrence Berkeley National Laboratory, became the first researchers to observe the motion of an atom's valence or outermost electrons in real-time by investigating the ejection of an electron from an atom by an intense laser pulse.

In the experiments, an electron in a krypton atom is removed by a laser pulse that lasts less than four femtoseconds (one femtosecond is one millionth of one billionth of a second). This process leaves behind an atom with a pulsating positively charged hole in the valence shell, which originates from electronic wave functions of the atom. The scientists led by Dr. Steve Leone, an ultrafast laser expert and the recent recipient of a National Security Science and Engineering Faculty Fellowship, used an extreme ultraviolet light pulse, the duration for which was 150 attoseconds (one attosecond is one billionth of one billionth of a second), to capture and photograph the movement of valence electrons for the first time.

This research into electron motions is expected to enable the scientists to better control processes and materials that will improve high-speed electronics and carbon-free energy sources that will benefit both the Air Force and consumers.

"If we want to understand high speed electronics, we need to work on changing molecular bonds in chemical reactions and the movement of electrons during chemical reactions or in complex solids which will only be possible by freezing time in a femtosecond," said Leone.

Dr. Michael R. Berman, program manager at AFOSR who is overseeing the scientists believes their research is an elegant example of the new capabilities of attosecond pulses to probe the dynamics of electron motions.

"This program and instrumentation will open new doors into probing fundamental physical processes on time scales faster than ever probed before."

Berman also noted, "These new tools will let us probe electron dynamics in materials and semiconductors and could help us understand and reduce electron loss processes to make electronics and devices like solar cells more efficient and to bring electronic data processing to its highest level."

ABOUT AFOSR: The Air Force Office of Scientific Research, located in Arlington, Virginia, continues to expand the horizon of scientific knowledge through its leadership and management of the Air Force's basic research program. As a vital component of the Air Force Research Laboratory, AFOSR's mission is to discover, shape, and champion basic science that profoundly impacts the future Air Force.

[decimon]

Pulsating ping.

[Talisker]

Single-atom assembly engineering.

Now THAT’s cooking!

[east1234]

Interesting, but why the hell is the Air Force spending money on this research?

[Mr. K]

Ok here’s one for the scientists here...

if an electron can only occupy certain valence shells within an atom, and ‘jumps’ from one quantum level to another, then what happens to an electron freed from an atom?

is it able to move without dissapearing at one place and reappearing at the next?

or does it become more of a wave when traveling? (wave/particle dual nature)

[The Cajun]

Damn, no picture at site. Willing to bet that sucker was hauling. Probably was just a pic of the aftereffect on the atom.

[Constitution Day]

Amazing! Thanks.

[evets]

Here's a diagram explaining the scientific concept.


... You're welcome.

[ComputerGuy]

The effort to understand the universe is one of the very few things that lifts human life a little above the level of farce, and gives it some of the grace of tragedy.

Nobel Laureate Steven Weinberg

[GeronL]

lol

[The Comedian]

Atto-boy! ping.

Frowning takes 68 muscles.
Smiling takes 6.
Pulling this trigger takes 2.
I'm lazy.

[Red_Devil 232]

"... one attosecond is one billionth of one billionth of a second ..."

How do they know?

[Oberon]

...a laser pulse that lasts less than four femtoseconds (one femtosecond is one millionth of one billionth of a second)

Here's a question: How long, in inches, is that pulse of laser light?

[EvilOverlord]

My understanding, not being a professional physicist, is that the electron is confined to one of several energy levels when it is bound to the atom. Applying enough energy to free the electron (known as the 'work function'), allows the electron to have any energy level, and can move freely.

Free space is essentially a continuum of an infinite number of very closely spaced energy levels that the electron can occupy.

An electron is a wave function when bound to the atom. It has no single position, but appears as an 'electron cloud' around the atom. The electron may appear to be a particle, or a wave, in free space, depending on its interactions with other matter, energy, and observers. It's always a particle and a wave. It's called wave-particle duality.

[ComputerGuy]

I’ll betcha it ain’t very far.

[decimon]

"... one attosecond is one billionth of one billionth of a second ..."

How do they know?

The answer takes too long. ;-)

[3niner]

Here's a question: How long, in inches, is that pulse of laser light?

About 0.00005 inches.

[whd23]

Post pics or it didn’t happen

[antiRepublicrat]

Here's a question: How long, in inches, is that pulse of laser light?

Thanks to Grace Hopper, I know a nanosecond of light is just under a foot long. A nanosecond is a billionth of a second, so this would be just under 1/250,000th of a foot, or 0.0000472 inches.

[MarkL]

Here's a question: How long, in inches, is that pulse of laser light?

It depends on whether it's being measured by a man or a woman!

Mark