Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chemists calculate structure of puzzling ’scrambler’ molecule

06.01.2006


Chemists have calculated the structure of a very unusual molecule, one whose hyperactive atoms have earned it the nickname “the scrambler.”



This highly caustic “protonated methane,” or CH5+, is also called a “super acid,” and it is a short-lived player in the chemical reactions that make petroleum products.

CH5+ should also be present in interstellar clouds where stars and planets form, said Anne B. McCoy, professor of chemistry at Ohio State University. McCoy hopes that the work she and her team are publishing in the current issue of the journal Science will one day give astronomers the tools they need to determine once and for all whether the molecule is really out there in space.


To identify chemicals on earth and in outer space, scientists record the spectrum of light absorbed by a molecule. Each molecule ever identified has its own unique spectrum, resembling lines in a bar code.

Since the 1960s, when petrochemical experiments suggested the existence of CH5+, scientists have been trying to record a complete spectrum of it, but the molecule won’t sit still. Scientists who tried to image CH5+ have found that it’s like a three-year-old child – impossible to photograph, except in a blur.

“CH5+ has five hydrogen atoms scrambling around a carbon atom that sits at the center,” McCoy explained. The hydrogen atoms are simultaneously rotating and vibrating.

Because the atoms are always on the move, scientists have difficulty interpreting the spectrum. Still, they have recorded several CH5+ spectra experimentally.

Study coauthors David Nesbitt, Chandra Savage, and Feng Dong of JILA, a joint research institute of the University of Colorado at Boulder and the National Institute of Standards and Technology, report the most recent and best resolved of these spectra to date in the Science paper. But in spite of this progress, researchers have not been able to match the lines in the CH5+ bar code to any specific motions of the molecule.

That’s what McCoy and Professor Joel M. Bowman of Emory University did mathematically. For certain features on the spectrum, they calculated what the motions must be.

The result is most complete vibrational spectra ever calculated – a theoretical picture of the molecule’s structure.

The chemists’ employed a unique strategy in their calculations.

“Although the hydrogen atoms are constantly scrambling, the overall range of types of structures can be characterized by three basic configurations,” McCoy said. One configuration corresponds to a low energy state for the molecule, and the other two to higher energy states. McCoy, Bowman, Ohio State graduate student Lindsay M. Johnson and Emory postdoctoral researcher Xinchuan Huang calculated spectra for all three structures.

That in itself was standard procedure, she said – but then they went on to examine the probability that the molecule would assume each of those three structures, and used that information to weight their calculations.

“It turns out that this was the crucial step,” McCoy said.

She acknowledged that her team hasn’t yet assembled a full picture of CH5+, since their calculations accounted for the vibration of the molecule but not its constant rotation. That will be their next step. If successful, they’ll have a complete theoretical view of what the molecule’s spectrum should look like.

“The ultimate goal of this work is to identify a kind of signature for CH5+,” McCoy said. “Once we have it, we can compare it to what is observed from astronomical measurements to determine its abundance in different regions of space.”

“From a more fundamental perspective, one thing that intrigues me is how we can characterize molecules like CH5+ that have no single well-defined structure and how this lack of a well-defined structure impacts its reactivity,” she continued.

She and her coauthors have started calculating what would happen when the hydrogen atoms in CH5+ are replaced with deuterium, also known as “heavy hydrogen.” They suspect that adding one or two heavy hydrogen atoms will stabilize the remaining hydrogen atoms and settle “the scrambler” down once and for all.

Anne B. McCoy | EurekAlert!
Further information:
http://www.osu.edu

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>