Featured Research

from universities, journals, and other organizations

Timely discovery: Physics research sheds new light on quantum dynamics

Date:
May 15, 2012
Source:
Kansas State University
Summary:
Physicists have made a breakthrough that improves understanding of matter-light interactions. Their research allows double ionization events to be observed at the time scale of attoseconds and shows that these ionization events occur earlier than thought -- a key factor to improve knowledge of correlated electron dynamics.

Artist's view of non-sequential double ionization. The 3D plots on the circle were obtained from experimental data and show how the velocities of the two electrons change with the electric-field evolution of the ionizing pulse. The plot in the center is the sum of all these single measurements. From these data, the scientists can reconstruct the detailed process of the double ionization.
Credit: Christian Hackenberger, Max-Planck-Institute for Quantum Optics

Kansas State University physicists and an international team of collaborators have made a breakthrough that improves understanding of matter-light interactions.

Their research allows double ionization events to be observed at the time scale of attoseconds, which are one-billionth of a billionth of a second. The physicists have also shown that these ionization events occur earlier than thought -- a key factor to improving knowledge of correlated electron dynamics, which involve two electrons and their interactions with each other. The work appears in a recent issue of Nature Communications.

"The research involves studying if these correlated electrons, ejected from an atom or a molecule, are traveling in the same or opposite directions," said Nora Johnson, a doctoral student in physics from Dell Rapids, S.D. "We can also determine if one electron has all the energy or if they share energy equally."

Other university researchers involved include Itzik Ben-Itzhak, university distinguished professor of physics, and Matthias Kling, assistant professor of physics. Kling is the principal investigator for the project and is on research leave at the Max Planck Institute of Quantum Optics in Garching, Germany, where he is performing related research. All of the researchers are involved with the university's James R. Macdonald Laboratory.

Double ionization occurs when two electrons are removed from an atom -- a process that can be caused by an intense laser pulse. When double ionization occurs in the laser field it can take the form of a sequential process, in which the laser removes one electron and then removes the other electron. This project focuses on another mechanism -- the nonsequential process for ionization -- in which the laser removes one electron, which is accelerated and hits a second electron to excite it. The laser then knocks out the second electron from the atom.

The researchers sent a four femtosecond-long laser pulse onto argon atoms. A femtosecond is a millionth of a billionth of a second. While most of the argon atoms were singly ionized, approximately every thousandth atom underwent nonsequential double ionization.

"The surprising result is that everybody expected that the second electron becomes excited and then, when the laser field is the strongest, this electron is removed," said Ben-Itzhak, director of the Macdonald laboratory. "But it actually happens earlier."

The researchers discovered that the time between the recollision and the second ionization is about 400 attoseconds. This is about 200 attoseconds earlier than the peak of the field, which is when physicists expected the second ionization to occur.

Johnson conducted her early experiments at the Macdonald Laboratory. She performed more extensive experiments during a 2009 Fulbright Fellowship at the Max Planck Institute of Quantum Optics. The two organizations have an ongoing collaboration and the Kansas State University team is directly funded by a $400,000 National Science Foundation grant.

"The key is that Nora has brought knowledge from Germany about short pulses and we can now continue these experiments in Kansas," Ben-Itzhak said. "We have an ongoing collaboration with them that goes both ways."

Now that the researchers have made an important discovery with atoms, Johnson is performing a similar experiment with molecules. She is performing experiments at the Macdonald Laboratory and will use the laboratory's expertise in imaging molecules.

"A molecule is more complex than an atom, which typically means its reaction dynamics are richer," Johnson said. "We are excited to pursue correlated electron dynamics at the next level of complexity to further understand them."


Story Source:

The above story is based on materials provided by Kansas State University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Boris Bergues, Matthias Kübel, Nora G. Johnson, Bettina Fischer, Nicolas Camus, Kelsie J. Betsch, Oliver Herrwerth, Arne Senftleben, A. Max Sayler, Tim Rathje, Thomas Pfeifer, Itzik Ben-Itzhak, Robert R. Jones, Gerhard G. Paulus, Ferenc Krausz, Robert Moshammer, Joachim Ullrich, Matthias F. Kling. Attosecond tracing of correlated electron-emission in non-sequential double ionization. Nature Communications, 2012; 3: 813 DOI: 10.1038/ncomms1807

Cite This Page:

Kansas State University. "Timely discovery: Physics research sheds new light on quantum dynamics." ScienceDaily. ScienceDaily, 15 May 2012. <www.sciencedaily.com/releases/2012/05/120515131721.htm>.
Kansas State University. (2012, May 15). Timely discovery: Physics research sheds new light on quantum dynamics. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2012/05/120515131721.htm
Kansas State University. "Timely discovery: Physics research sheds new light on quantum dynamics." ScienceDaily. www.sciencedaily.com/releases/2012/05/120515131721.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Newsy (July 28, 2014) — Stanford University published its findings for a "pure" lithium ion battery that could have our everyday devices and electric cars running longer. Video provided by Newsy
Powered by NewsLook.com
The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) — AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) — Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) — Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

More Coverage


Billiard Game in an Atom: Physicists Trace Double Ionization of Argon Atoms on Attosecond Time Scales

May 8, 2012 — Physicists have traced the double ionization of argon atoms on attosecond time scales. When an intense laser pulse interacts with an atom it generates agitation on the micro scale. The most likely ... read more
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins