Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Skipping Atomic-scale Stones to Study Some Chemistry Basics

Computer simulation of the JILA gas-liquid scattering experiments uses long molecules tethered to a surface as a useful stand-in for liquids, which are too complex for computer modeling. The speed of rotation of the carbon dioxide molecule after striking the surface is strongly dependant on its orientation, an effect caused by atomic-scale “waves” on the fluid surface.
Computer simulation of the JILA gas-liquid scattering experiments uses long molecules tethered to a surface as a useful stand-in for liquids, which are too complex for computer modeling. The speed of rotation of the carbon dioxide molecule after striking the surface is strongly dependant on its orientation, an effect caused by atomic-scale “waves” on the fluid surface.

Abstract:
Thought experiment: a carbon dioxide molecule—think of a cheerleader's baton—comes slanting in at high speed over a dense liquid, strikes the surface and ricochets. How does it tumble? Fast or slow? Forward, backward or sideways? These are not idle questions because simple events like the tumbling molecule go to the heart of the chemistry and physics of gas-liquid interactions. These cover a broad swath of important chemical processes—including breathing—for which details of the encounter are just coming into view.

Skipping Atomic-scale Stones to Study Some Chemistry Basics

GAITHERSBURG, MD | Posted on August 6th, 2008

New experiments reported this week* from JILA in Boulder, Colo., are giving a uniquely detailed look at what happens when gas molecule meets fluid.

Historically, chemistry has been confined to observing the mass behavior of huge numbers of molecules—mix things together, look at the reaction products, infer what happened. Only in the past couple of decades have powerful lasers made it possible to "watch" specific events involving only a few molecules. Today, they can even observe the role played by a molecule's shape, a critical influence in many interactions.

Now, Bradford Perkins, Jr., of the University of Colorado and David Nesbitt of the National Institute of Standards and Technology (NIST) report the first direct observation of the rotational dynamics of a molecule bouncing off a liquid surface.

Perkins and Nesbitt directed a beam of carbon dioxide molecules at a pool of synthetic fluorinated fluid in a vacuum. The molecules that bounced off passed through an infrared laser beam, which switched rapidly between alternate orientations, or polarization states. A sensitive detector measured how much light was absorbed by the passing molecules.

A rod-like carbon dioxide molecule will absorb with slightly different efficiencies depending on how it rotates relative to the light's polarization. Analyzing the oscillating signal allowed the team to observe just how fast and in what direction the molecules were tumbling after hitting the fluid. They found the molecules had a pronounced tendency for a forward, end-over-end "top spin," as if hit by a star Wimbledon tennis player, with the rate of tumbling strongly correlated with how its molecular rotation is aligned relative to the light path.

"To know how this happens at the molecular level—how things bounce, skip, spin, tumble, push and pull—represents a big leap in our understanding," says Nesbitt. "Experiments of this sort help build that understanding."

In addition, Nesbitt says, observing how gas molecules of different shapes twist and rotate after striking a liquid reveals a lot about the nature of the fluid surface—how "rough" it is from the disturbance of microscopic waves and how that roughness affects interactions with gases.

JILA is a research institution operated jointly by NIST and the University of Colorado. The research was supported by the Air Force Office of Scientific Research and the National Science Foundation.

* B.G. Perkins, Jr., and D.J. Nesbitt. Stereodynamics in state-resolve scattering at the gas-liquid interface. Proceedings of the National Academy of Science, Early Edition.

####

About NIST
Founded in 1901, NIST is a non-regulatory federal agency within the U.S. Department of Commerce. NIST's mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.

For more information, please click here

Contacts:
Michael Baum

(301) 975-2763

Copyright © NIST

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

MOVIE CLIP - click to play

Related News Press

News and information

Nano-supercapacitors for electric cars July 25th, 2014

New imaging agent provides better picture of the gut July 25th, 2014

Breakthrough laser experiment reveals liquid-like motion of atoms in an ultra-cold cluster: University of Leicester research team unlocks insights into creation of new nano-materials July 25th, 2014

Scientists Test Nanoparticle "Alarm Clock" to Awaken Immune Systems Put to Sleep by Cancer July 25th, 2014

Chemistry

Oregon chemists eye improved thin films with metal substitution: Solution-based inorganic process could drive more efficient electronics and solar devices July 21st, 2014

Fundamental Chemistry Findings Could Help Extend Moore’s Law: A Berkeley Lab-Intel collaboration outlines the chemistry of photoresist, enabling smaller features for future generations of microprocessors July 15th, 2014

Videos/Movies

More than glitter: Scientists explain how gold nanoparticles easily penetrate cells, making them useful for delivering drugs July 21st, 2014

"Nanocamera" takes pictures at distances smaller than light's own wavelength: How is it possible to record optically encoded information for distances smaller than the wavelength of light? July 17th, 2014

CIQUS researchers develop an extremely simple procedure to obtain nanosized graphenes July 15th, 2014

Govt.-Legislation/Regulation/Funding/Policy

New imaging agent provides better picture of the gut July 25th, 2014

A*STAR and industry form S$200M semiconductor R&D July 25th, 2014

NNCO Announces an Interactive Webinar: Progress Review on the Coordinated Implementation of the National Nanotechnology Initiative 2011 Environmental, Health, and Safety Research Strategy July 23rd, 2014

Nano-sized Chip "Sniffs Out" Explosives Far Better than Trained Dogs: TAU researcher's groundbreaking sensor detects miniscule concentrations of hazardous materials in the air July 23rd, 2014

Discoveries

New imaging agent provides better picture of the gut July 25th, 2014

Breakthrough laser experiment reveals liquid-like motion of atoms in an ultra-cold cluster: University of Leicester research team unlocks insights into creation of new nano-materials July 25th, 2014

Scientists Test Nanoparticle "Alarm Clock" to Awaken Immune Systems Put to Sleep by Cancer July 25th, 2014

Iranian Scientists Produce Transparent Nanocomposite Coatings with Longer Lifetime July 24th, 2014

Announcements

Nano-supercapacitors for electric cars July 25th, 2014

New imaging agent provides better picture of the gut July 25th, 2014

Breakthrough laser experiment reveals liquid-like motion of atoms in an ultra-cold cluster: University of Leicester research team unlocks insights into creation of new nano-materials July 25th, 2014

Scientists Test Nanoparticle "Alarm Clock" to Awaken Immune Systems Put to Sleep by Cancer July 25th, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE