Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New details of atomic structure of water under extreme conditions found

15.03.2013
Scientist from Dortmund, Helsinki, Potsdam, and the ESRF have revealed details of the microscopic atomic structure of water under extreme conditions. The results have now been published in the Proceedings of the National Academy of Sciences of the USA.

Liquid water remains a mystery even after decades of dedicated scientific investigations and researchers still struggle to fully describe its unusual structure and dynamics. At high temperatures and high pressures, water is in the so called supercritical state and exhibits a number of peculiar characteristics that are very unlike from water at ambient conditions.

In this state water is a very aggressive solvent, enabling chemical reactions impossible otherwise, e.g. the oxidization of hazardous waste or the conversion of aqueous biomass streams into clean water and gases like hydrogen and carbon dioxide.

High temperature and high pressure conditions can also be found inside the Earth, in its lower crust and upper mantle. Here, the unique properties of supercritical water have been believed to play a key role in the transfer of mass and heat as well as in the formation of ore deposits and volcanoes. Supercritical water is even thought to have contributed to the origin of life.

Knowledge of the structural properties of water on an atomic scale under these extreme conditions of high temperature and high pressure may become very helpful in understanding these processes, says Christoph Sahle, from the Department of Physics at the University of Helsinki and a member of the research team behind the new results.

Spectroscopic investigations confirm previous theoretical model

Now, a research team of scientists from the Technische Universität Dortmund, Germany, the University of Helsinki, Finland, the Deutsches GeoForschungsZentrum in Potsdam, Germany, and the European Synchrotron Radiation Facility (ESRF), Grenoble, France, have used x-ray spectroscopy to study the structural properties of water in the supercritical state.

Conventional spectroscopic analyses can provide key insights into the atomic structure of a substance, however, these techniques are not well suited to studying water under supercritical conditions because of the complicated sample environments in which supercritical water has to be contained. Using the intense x-ray radiation from the ESRF for inelastic x-ray scattering spectroscopy and a new technique that makes it possible to look at the chemistry of water inside a complex environment together with a quantum mechanical modeling framework known as density functional theory, the group of scientists has made these spectroscopic investigations of water at high temperature and high pressure feasible.

The researchers found that the measured inelastic x-ray scattering spectra evolve systematically from liquid-like at ambient conditions to more gas-like at high temperatures and pressures. To learn more about the local atomic structure of water at the tested conditions, theoretical inelastic x-ray scattering spectra from computer simulations were calculated and compared to the experimental data. All features found in the experimental data and the systematic changes of these features as a function of temperature and pressure could be reproduced by the calculation.

Based on this close resemblance of the calculated and measured data, the authors extracted detailed information about the atomic structure and bonding. They could show that, according to the theoretical model, the microscopic structure of water remains homogeneous throughout the range of examined temperatures and pressures.

The presented findings also implicate means to study unknown disordered structures and samples under extreme conditions on an atomic scale in depth even when other structural probing techniques fail.

Read more: Microscopic Structure of Water at Conditions of the Earth's Crust and Mantle, http://www.pnas.org/content/early/2013/03/07/1220301110

Additional information:

Christoph Sahle
tel. 358-9-191-59641
Yours truly,
Minna Meriläinen-Tenhu
Press officer
University of Helsinki
minna.merilainen@helsinki.fi

Christoph Sahle | EurekAlert!
Further information:
http://www.helsinki.fi

More articles from Earth Sciences:

nachricht Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft

nachricht How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>