Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Putting the squeeze on nitrogen for high energy materials

05.09.2008
Nitrogen atoms like to travel in pairs, hooked together by one of the strongest chemical bonds in nature. By subjecting nitrogen molecules to extreme temperatures and pressures scientists are getting a new understanding of not only nitrogen but other similar molecules, including hydrogen.

In the current online edition of Physical Review Letters, researchers from the Carnegie Institution's Geophysical Laboratory report changes in the melting temperature of solid nitrogen at pressures up to 120 gigapascals (more than a million atmospheres) and temperatures reaching 2,500° Kelvin (more than 4000° Fahrenheit).

These results, plus observed changes in the structure of solid nitrogen at high pressures, could lead to new high energy nitrogen- or hydrogen-based fuels in the future. Hypothesized nitrogen polymers could form materials with higher energy content than any known non-nuclear material.

Alexander Goncharov, Viktor Struzhkin, and Russell Hemley from Carnegie, with Jonathan Crowhurst from Lawrence Livermore National Laboratory, compressed liquid nitrogen in a device known as a diamond anvil cell, which generates ultrahigh pressures by squeezing a sample between two gem-quality diamonds. Because the diamonds are transparent to most wavelengths of light, the sample can be heated by a laser during the experiment. A technique called Raman spectroscopy uses light emitted by the heated sample to analyze changes in the sample's molecular structure as they occur.

"Until now, no one had made these kinds of in situ observations of nitrogen at such extreme temperatures and pressures," says Goncharov. "Our measurements of the melting line and the vibration properties of the fluid indicated by the Raman spectroscopy give us a very clear picture of how nitrogen and its molecular bonds respond under these conditions."

A chart of the temperatures and pressures at which a substance changes from one phase to another (from liquid to gas, from one crystal structure to another, and so on) is called a phase diagram. For nitrogen, as well as most other materials, the high temperature and pressure regions of the phase diagram are relatively unexplored territories. Researchers hope that these unexplored regions may harbor new materials with useful properties.

At room temperature and atmospheric pressure, nitrogen is a gas, but it can be cooled and compressed to form a liquid or a solid, depending on the temperature and pressure. Even as it changes phases, however, the nitrogen remains a two atom (diatomic) molecule, held together by a strong—and energy rich—triple bond.

"Nitrogen compounds tend to be high energy density materials," says Goncharov. "Pure nitrogen can be a powerful fuel or explosive if one can figure out how to associate nitrogen atoms in a material other than as a triple-bonded diatomic molecule. Recent experiments have shown that nitrogen transforms to nonmolecular single-bonded phases at very high pressure. These could serve as high energy density materials if preserved on a return to ambient pressure. Our results will help show the way to synthesize these materials at less extreme conditions."

Filling the gaps in nitrogen's phase diagram has implications for the study of other critical materials, say Goncharov. "Nitrogen is an archetypal diatomic molecule. Knowledge of its phase diagram and other properties gives a hint about the behavior of other diatomics, among which is hydrogen. Many key transformations and other phenomena occur in nitrogen at much lower pressures than in hydrogen," he says. "Hydrogen is a fuel for the future. It is theorized to have fascinating properties under high pressure, including transformation to metallic, superconducting and superfluid states. Whether the materials with such properties can be recovered and stabilized at ambient pressure remains an open question. But with nitrogen, we are moving ahead quickly. "

Alexander Goncharov | EurekAlert!
Further information:
http://www.ciw.edu

More articles from Physics and Astronomy:

nachricht Tangled magnetic fields power cosmic particle accelerators
14.12.2018 | DOE/SLAC National Accelerator Laboratory

nachricht In search of missing worlds, Hubble finds a fast evaporating exoplanet
14.12.2018 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Data use draining your battery? Tiny device to speed up memory while also saving power

14.12.2018 | Power and Electrical Engineering

Tangled magnetic fields power cosmic particle accelerators

14.12.2018 | Physics and Astronomy

In search of missing worlds, Hubble finds a fast evaporating exoplanet

14.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>