Featured Research

from universities, journals, and other organizations

Scientists Demonstrate New Way To Control Chemical Reactions

Date:
June 2, 2003
Source:
Brookhaven National Laboratory
Summary:
Using a low-temperature scanning tunneling microscope (STM) to selectively “tweak” the vibrations of individual molecules, scientists have demonstrated a new way to directly influence the outcome of chemical reactions. The ability to exert such control may one day allow scientists to eliminate unwanted byproducts or selectively produce end products with potential commercial value.

UPTON, NY — Using a low-temperature scanning tunneling microscope (STM) to selectively “tweak” the vibrations of individual molecules, scientists have demonstrated a new way to directly influence the outcome of chemical reactions. The ability to exert such control may one day allow scientists to eliminate unwanted byproducts or selectively produce end products with potential commercial value.

Zhen Song, now a research associate at the U.S. Department of Energy’s Brookhaven National Laboratory, used the technique to investigate the desorption of ammonia molecules from a copper surface while working with collaborators* at the Fritz-Haber-Institut der Max-Planck-Gesellschaft in Berlin, Germany. The work is described in the May 29, 2003, issue of Nature.

By detecting and controlling the tunneling electrons running between tip and sample, STM techniques enable scientists not only to measure the structure of materials on an atomic level, but also to manipulate molecules individually on the substrate.

“We selected a chemisorbed ammonia molecule on a copper surface under the microscope and used the tip of the STM to excite vibrations of the molecule,” said Song. “We found that the motion of the molecule can be controlled by tuning the parameters of the tunneling electrons: the electronic current and energy.”

Above a certain threshold energy, the tunneling electrons induced one mode of molecular vibration that resulted in a movement of the ammonia molecules to new positions on the copper surface. Below the threshold, the electrons induced a different mode of vibration that allowed the ammonia molecules to completely disassociate from the copper.

“We are able to select a particular reaction pathway by adjusting the electronic tunneling current and energy,” Song said.

This is the first example of using STM in mode-selective chemistry, a field that has previously been dominated by laser techniques. Using STM, the study of the reaction mechanism can be achieved with very low power irradiation, and the monitoring of the reaction is limited to a single molecule. This approach is complementary to the conventional laser techniques used in the study of mode-selective chemistry.

“It would be interesting to extend this methodology to more complex processes, for example, by searching for strategies of controlling and enhancing reactivity at surfaces through the discovery of new reaction pathways that are inaccessible via classical ‘thermal’ chemistry,” said Song.

* This research was a collaboration among scientists at the Fritz-Haber-Institut, Germany, the Consejo Superior de Investigaciones Cientνficas, Spain, the Universit Paul Sabatier, France, and Brookhaven National Laboratory.

The U.S. Department of Energy's Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies. Brookhaven also builds and operates major facilities available to university, industrial, and government scientists. The Laboratory is managed by Brookhaven Science Associates, a limited liability company founded by Stony Brook University and Battelle, a nonprofit applied science and technology organization.


Story Source:

The above story is based on materials provided by Brookhaven National Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

Brookhaven National Laboratory. "Scientists Demonstrate New Way To Control Chemical Reactions." ScienceDaily. ScienceDaily, 2 June 2003. <www.sciencedaily.com/releases/2003/06/030602025508.htm>.
Brookhaven National Laboratory. (2003, June 2). Scientists Demonstrate New Way To Control Chemical Reactions. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2003/06/030602025508.htm
Brookhaven National Laboratory. "Scientists Demonstrate New Way To Control Chemical Reactions." ScienceDaily. www.sciencedaily.com/releases/2003/06/030602025508.htm (accessed September 2, 2014).

Share This




More Matter & Energy News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Google Teases India Event, Possible Android One Reveal

Google Teases India Event, Possible Android One Reveal

Newsy (Sep. 1, 2014) — Google has announced a Sept. 15 event in India during which they're expected to reveal their Android One phones. Video provided by Newsy
Powered by NewsLook.com
Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) — Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) — Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) — Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
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:
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