Featured Research

from universities, journals, and other organizations

Canadian Discovery Allows Scientists To Watch The Ultrafast Processes Of The Microworld

Date:
September 7, 1999
Source:
National Research Council Of Canada
Summary:
Scientists at the National Research Council of Canada have developed a technique that allows them to follow the ultrafast internal processes that lead to electronic-structural rearrangements in molecules.

(OTTAWA - September 2, 1999) -- Scientists at the National Research Council of Canada have developed a technique that allows them to follow the ultrafast internal processes that lead to electronic-structural rearrangements in molecules. This discovery, which may eventually provide insights into the new field of "molecular electronics" and biologicial processes such as vision and photosynthesis, was made by a multidisciplinary team of physicists and chemists at NRC's Steacie Institute for Molecular Sciences (SIMS). Their work was reported in the September 2 issue of Nature.

This SIMS group specializes in femtosecond laser technology, molecular dynamics and intense field physics. A femtosecond (10-15 s) is an extremely short duration: one femtosecond is to one minute as one minute is to the age of the universe. Modern lasers can now routinely produce pulses in this range.

The Nature article describes a new femtosecond technique for following and distinguishing the electronic rearrangements and atomic motions in a molecular process, even though they occur on the same time scale. The idea is to use ionization (removal of an electron) to get a picture of what the molecule was doing at the moment of ionization. By measuring the removed electron with a technique called photoelectron spectroscopy, Dr. Albert Stolow and co-workers were able to follow both the atomic motions and the electronic rearrangements that accompany them.

Femtoseconds are the time scale for ultrafast chemical reactions and internal motions in molecules. When a molecule is excited, both its atoms and electrons can begin to move. The electrons, being very light and fast, might easily adjust to the motions of the much heavier atoms. In many important cases, however, the electronic rearrangements and atomic motions occur on the same time scale, making it difficult to discern what is happening. Femtosecond lasers are used as an ultrafast stroboscope to watch the molecular motions as they occur. One laser pulse starts the process and a second takes a 'snapshot' at a later time. This is repeated until the whole time behaviour is known. If a femtosecond 'snapshot' were recorded of the atomic motion only, we would be missing the critical element of how the electrons are rearranging at the same time.

According to Dr. Albert Stolow, the project leader, there is a world wide effort in the development of increasingly smaller devices for information and telecommunications technology. "Such devices will soon be so small that they begin to approach the size of molecules. As such, the molecular way of thinking becomes increasingly profitable," said Dr. Stolow. The burgeoning field of 'molecular electronics' considers molecules themselves as electronic devices and, using fundamental physical principles, tries to lay the foundation for the next generation of devices.

Femtosecond time scale processes underlie many of the phenomena we see around us in the natural world. Vision and photosynthesis are interesting cases because they are both biological systems and paradigms for molecular electronics. In both these cases, a complex mixing of atomic and electronic motions is critical to the function.

"We will seldom be interested only in the static properties of molecular systems. We want to know how they change as a function of time, in other words, their dynamics," said Dr. Stolow. The design of active molecular scale devices must include consideration of these dynamics process. Another critical issue in molecular systems is long term stability. Excited molecules have many undesired paths they can follow. The design of stable, efficient devices requires the rates of decay (e.g. breaking) to be much slower than the rate of the desired process (e.g. switching). We expect that fundamental studies will shed new light onto complex chemical and biological processes as well as open new avenues for the rational design of molecular devices."


Story Source:

The above story is based on materials provided by National Research Council Of Canada. Note: Materials may be edited for content and length.


Cite This Page:

National Research Council Of Canada. "Canadian Discovery Allows Scientists To Watch The Ultrafast Processes Of The Microworld." ScienceDaily. ScienceDaily, 7 September 1999. <www.sciencedaily.com/releases/1999/09/990907074029.htm>.
National Research Council Of Canada. (1999, September 7). Canadian Discovery Allows Scientists To Watch The Ultrafast Processes Of The Microworld. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/1999/09/990907074029.htm
National Research Council Of Canada. "Canadian Discovery Allows Scientists To Watch The Ultrafast Processes Of The Microworld." ScienceDaily. www.sciencedaily.com/releases/1999/09/990907074029.htm (accessed October 22, 2014).

Share This



More Matter & Energy News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Newsy (Oct. 21, 2014) If you've ever watched "Back to the Future Part II" and wanted to get your hands on a hoverboard, well, you might soon be in luck. Video provided by Newsy
Powered by NewsLook.com
Robots to Fly Planes Where Humans Can't

Robots to Fly Planes Where Humans Can't

Reuters - Innovations Video Online (Oct. 21, 2014) Researchers in South Korea are developing a robotic pilot that could potentially replace humans in the cockpit. Unlike drones and autopilot programs which are configured for specific aircraft, the robots' humanoid design will allow it to fly any type of plane with no additional sensors. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Graphene Paint Offers Rust-Free Future

Graphene Paint Offers Rust-Free Future

Reuters - Innovations Video Online (Oct. 21, 2014) British scientists have developed a prototype graphene paint that can make coatings which are resistant to liquids, gases, and chemicals. The team says the paint could have a variety of uses, from stopping ships rusting to keeping food fresher for longer. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
China Airlines Swanky New Plane

China Airlines Swanky New Plane

Buzz60 (Oct. 21, 2014) China Airlines debuted their new Boeing 777, and it's more like a swanky hotel bar than an airplane. Enjoy high-tea, a coffee bar, and a full service bar with cocktails and spirits, and lie-flat in your reclining seats. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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