Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers explain odd oxygen bonding under pressure

06.08.2008
Oxygen, the third most abundant element in the cosmos and essential to life on Earth, changes its forms dramatically under pressure transforming to a solid with spectacular colors. Eventually it becomes metallic and a superconductor.

The underlying mechanism for these remarkable phenomena has been fascinating to scientists for decades; especially the origin of the recently discovered molecular cluster (O2)4 in the dense solid, red oxygen phase.

Researchers from the Carnegie Institution's Geophysical Laboratory (GL), with colleagues* found that under pressure the molecules interact through their outermost electron clouds or "orbitals." Using a newly developed synchrotron technique at HPCAT, the lab's synchrotron facility at Argonne National Laboratory, the researchers found that the interaction of these half-filled orbitals increases with increasing pressure, changing the location of the orbitals, and bringing the four oxygen molecules together to form the (O2)4 clusters at a pressure about 10,000 times the atmospheric pressure (10 gigapascals). The study is published the week of August 4, in the Proceedings of the National Academy of Sciences.

"The molecular interaction in oxygen revealed by this study is due to the unique fact that oxygen's outmost orbital is half-filled with two unpaired electrons," explained Yue Meng, lead author of the study at HPCAT. "As the molecules are squeezed into smaller volumes at high pressure, electrons in the orbital inevitably move about, trying to pair with electrons in the neighboring molecules."

To study the dense solid phases of oxygen, the researchers developed the high-pressure inelastic X-ray scattering technique at the Advanced Photon Source, a high-brilliance synchrotron X-ray facility at Argonne. The technique uses the synchrotron X-ray beam to probe the electronic bonding change as a diamond anvil cell subjects a sample to many hundreds of thousands of atmospheres. The researchers combined their experimental results with theoretical calculations by collaborators to further reveal that there is an increasing interactions between the neighboring (O2)4 clusters in the red-colored oxygen, providing a mechanism for forming new bonding between the oxygen clusters in still higher pressure phases.

"The behavior of oxygen at high pressure demonstrates one of the most profound effects of pressure on matter, which transforms the colorless air we breath into colorful dense solids," continued Meng. "The drastic change in the appearance of this familiar gas is due to the bonding changes in oxygen induced by high pressure."

"This is the first demonstration of how new tools can be used to probe the subtle interactions between atoms and molecules that lead to the formation of entirely new crystal structures," said Russell J. Hemley, the GL's director. "These new structures may give rise to entirely new electronic, magnetic, and other physical properties that could lead to new technologies."

The formation of molecular clusters through the anti-bonding orbital called ?* is well known in organic chemistry and the electron delocalization in cluster orbitals provides several potentials for technical applications. "It is exciting to find that oxygen forms molecular clusters under high pressure through similar mechanism and this opens a possibility for new forms of materials at high pressure with potential for technical applications," Meng concluded.

Yue Meng | EurekAlert!
Further information:
http://www.hpcat.aps.anl.gov
http://www.CIW.edu

More articles from Earth Sciences:

nachricht GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center

nachricht Cyclic change within magma reservoirs significantly affects the explosivity of volcanic eruptions
30.11.2016 | Johannes Gutenberg-Universität Mainz

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

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

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>