Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Watching Electrons Move in Real Time

22.09.2010
At its most basic level, understanding chemistry means understanding what electrons are doing. Research published in The Journal of Chemical Physics not only maps the movement of electrons in real time but also observes a concerted electron and proton transfer that is quite different from any previously known phase transitions in the model crystal, ammonium sulfate. By extending X-ray powder diffraction into the femtosecond realm, the researchers were able to map the relocation of charges in the ammonium sulfate crystal after they were displaced by photoexcitation.

"Our prototype experiment produces a sort of 'molecular movie' of the atoms in action," says author Michael Woerner of the Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie in Germany. "The time and spatial resolution is now at atomic time and length scales, respectively."

Electron positions were mapped by observing the diffraction of X-ray pulses lasting tens of femtoseconds (quadrillionth of a second). Positions of protons and other nuclei were deduced from the locations of regions of high electron density. Within the crystal, the excited electrons transferred from the sulfate groups to a tight channel within crystal matrix. This channel was stabilized by the transfer of protons from adjacent ammonium groups into the channel. This transfer mechanism had not been previously observed or proposed, and the researchers had expected to see much smaller displacements.

According to Woerner, the technique should be applicable to structural studies of materials ranging from biomolecules to high-temperature superconductors. "We expect that the technique will be applied to many interesting material systems." He says. "In principle, femtosecond X-ray powder diffraction can be applied to any crystalline form of matter. Only the complexity of crystals and the presence of heavy elements, which reduces the penetration depth of X-rays, set some constraints."

The Article, "Concerted electron and proton transfer in ionic crystals mapped by femtosecond x-ray powder diffraction" by Michael Woerner, Flavio Zamponi, Zunaira Ansari, Jens Dreyer, Benjamin Freyer, Mirabelle Premont-Schwarz, and Thomas Elsaesser is published in The Journal of Chemical Physics.

See: http://jcp.aip.org/jcpsa6/v133/i6/p064509_s1

Journalists may request a free PDF of this article by contacting jbardi@aip.org

NOTE: An image is available for journalists. Please contact jbardi@aip.org

Image Caption: Sectional view of the charge density map Dr ( x , y , z , t ) for a plane which is parallel to the z-axis and includes the line connecting the hydrogen atoms of opposite NH + 4 groups for different time delays.

ABOUT THE JOURNAL OF CHEMICAL PHYSICS
The Journal of Chemical Physics publishes concise and definitive reports of significant research in methods and applications of chemical physics. Innovative research in traditional areas of chemical physics such as spectroscopy, kinetics, statistical mechanics, and quantum mechanics continue to be areas of interest to readers of JCP. In addition, newer areas such as polymers, materials, surfaces/interfaces, information theory, and systems of biological relevance are of increasing importance. Routine applications of chemical physics techniques may not be appropriate for JCP. Content is published online daily, collected into four monthly online and printed issues (48 issues per year); the journal is published by the American Institute of Physics. See: http://jcp.aip.org/
ABOUT AIP
The American Institute of Physics is a federation of 10 physical science societies representing more than 135,000 scientists, engineers, and educators and is one of the world's largest publishers of scientific information in the physical sciences. Offering partnership solutions for scientific societies and for similar organizations in science and engineering, AIP is a leader in the field of electronic publishing of scholarly journals. AIP publishes 12 journals (some of which are the most highly cited in their respective fields), two magazines, including its flagship publication Physics Today; and the AIP Conference Proceedings series. Its online publishing platform Scitation hosts nearly two million articles from more than 185 scholarly journals and other publications of 28 learned society publishers.

Jason Socrates Bardi | Newswise Science News
Further information:
http://www.aip.org

Further reports about: AIP Chemical Chemical Physics Physic Watching X-ray microscopy electrons hydrogen atom real estate

More articles from Physics and Astronomy:

nachricht A better way to weigh millions of solitary stars
15.12.2017 | Vanderbilt University

nachricht A chip for environmental and health monitoring
15.12.2017 | Friedrich-Alexander-Universität Erlangen-Nürnberg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>