Scientists Measure Movement in Split of a Millionth of a Second

[On the Road]

VIENNA (AFP) - Austro-Hungarian physicist Ferenc Krauzs said scientists had developed a device that can measure the speed of atomic processes down to the smallest fraction of a second yet.

Describing the device as "the fastest stopwatch in the world", Krauzs said Thursday that it measures the movement of atomic particles in time units smaller than 100 attoseconds. An attosecond is the name given to a quintillionth, or a millionth of a millionth of a millionth, of a second. "This time is to a second what a minute is to the age of the universe," Krauzs explained.

---snip

Whereas modern microscopes allow scientists to look at atoms at rest, the device allows them to record changes in atomic structure that happens so fast that it could not be documented before. "Our aim is to trace the movement of electrons inside atoms in real time. We need very short bursts of time to take shots of attoseconds," he told AFP.

http://story.news.yahoo.com/news?tmpl=story&cid=1539&ncid=1539&e=2&u=/afp/20040226/sc_afp/austria_science_time_040226160150

This stuff is amazing. Now we may be able to film the movements of electrons inside and atom.

[Superfly]

1. That's crazy cool.

[treepig]

2. i suppose if an electron can be seen with a microscope

that pretty much puts to rest the age old debate about whether they are particles or waves. on the other hand, this could be another of those stories on science-related matters that are so dumbed-down upon presentation in the media as to be rendered completely meaningless.

oh well, at least they had an interesting picture of

"A black-hole-powered jet of electrons and other sub-atomic particles traveling at nearly the speed of light"

accompanying the article (although its relevance topic at hand does remain a bit fuzzy as well).

[NNadir]

7. There really is not a debate as such.

For certain properties it is useful to think of electrons as waves. Orbitals, the things that determine directionality in molecules for instance are conveniently visualized as being the square of a wave function, a mathematical formalism associated with wave behavior. Electrons can be experimentally determined to have wave properties; they can for instance cancel one another out much as waves do when they interact.

For other purposes it is useful to think of them as particles. Electrons have momenta and they have charge and mass. These can be measured in other types of experiments. One can "weigh" electrons for instance. An electron cannot in fact be visualized. The attempt to look at an electron changes it. This is the basic idea underlying the Heisenberg Principle.

This is literally a duality and there is no question of "either/or". The nature of electrons is not constrained by the means we understand them by mirroring the macroscopic world with which we are more immediately familiar.

[GAspnes]

3. nowhere near Planck time

Planck time is the time it would take a photon travelling at the speed of light to across a distance equal to the Planck length. This is the ‘quantum of time’, the smallest measurement of time that has any meaning, and is equal to 10^-43 seconds. No smaller division of time has any meaning. With in the framework of the laws of physics as we understand them today, we can say only that the universe came into existence when it already had an age of 10^-43 seconds.

[Dogmudgeon]

4. Can that be done?

I know it would be quite an achievement to be able to "photograph" atoms and molecules, but isn't Schroedenger's Law pretty robust? That you can't know the location AND the momentum of a subatomic particle at the same time?

--bkl

[Waistdeep]

5. You're not going to "film" movement like that

The energy of a photon of light (the x-ray) which can resolve the position of an electron to a distance of say, 1/100 the radius of a hydrogen atom will have roughly several hundred thousand times the energy to ionize that atom. The electron will be zooming off somewhere as a result of the measurement. The Heisenberg uncertainly principle holds just fine. You can measure where it was as accurately as you want, but you can't also measure it's momentum at the same time.

A way of thinking about it is, if you try to make a movie, you will destroy the subject after one frame.

[Waistdeep]

6. Here's a real report

That Yahoo article was so unhelpful. What the guy has done is to figure out a way to reproducibly excite VIBRATIONAL and ROTATIONAL modes in atoms and molecules. So you can "film" atoms and molecules, perhaps even chemical reactions, but not individual electron movements.

From The American Institute of Physics Bulletin of Physics News
Number 625 February 19, 2003:

FROM FEMTOCHEMISTRY TO ATTOPHYSICS. Amid a fast game in a vast venue,
sports photography seeks to freeze motion and isolate small portions of space for special consideration. In the scientific world of the ultrafast and ultrasmall, stroboscopic effects are achieved with greatly attenuated laser pulses. The advent of laser light served up in femtosecond (or 10^-15. second) bursts has helped to elucidate the molecular world by freezing their vibrational and rotational motions. Scientists would of course like to instigate and monitor even shorter times and distances

A collaboration between scientists at the Technical University of Vienna and the Max Planck Institute for Quantum Optics (MPQ) has now done precisely this. They have produced a series of 2.5-fsec pulses, each consisting of only a few cycles of a carrier light signal modulated within an amplitude envelope. In the case of the Vienna-MPQ experiment, however, all the pulses are identical (a feat not achieved previously) and the phase of the carrier wave within the envelope is controlled with a time resolution of about 100
attoseconds. When the intense (100 GW) few-cycle pulse strikes an atom, an electron can be stripped away quickly, and reabsorbed just as quickly. This violent excursion results in the emission of a sharp x-ray spike with a duration even shorter than the pulse that excited the reaction. In fact the x-ray pulses are about 500 attoseconds long. Moreover, because all the waveforms of the optical pulse are identical, and controlled, the subsequent electron motions and x-ray emissions are also highly controlled and reproducible. At a talk at this week's meeting of the American Association for the Advancement of Science (AAAS) in Denver, Vienna physicist Ferenc Krausz said that this sub-femtosecond control of electron currents represented true attophysics, a new technique for directing and watching atomic processes at unprecedentedly short time intervals. (See Baltuska et al., Nature, 6
February 2003.)