Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The smallest piece of ice reveals its true nature

22.06.2007
Collaborative research between scientists in the UK and Germany (published in this week’s Nature Materials) has led to a breakthrough in the understanding of the formation of ice. Dr Angelos Michaelides of the London Centre for Nanotechnology (formerly of the Fritz-Haber Institut der Max-Planck Gesellschaft in Berlin) and Professor Karina Morgenstern of the Leibniz University Hannover have combined experimental observations with theoretical modelling to reveal with unprecedented resolution the structures of the smallest pieces of ice that form on hydrophobic metal surfaces.

The results provide information about the process of ice nucleation at a molecular level and take science a significant step closer to understanding the mysterious process through which ice forms around microscopic dust particles in the upper atmosphere. Because this is the basis of cloud formation, knowing how different particles promote ice formation is crucial for climate change models.

The authors began by cooling down a metallic surface to 5 degrees above absolute zero (around –268 Celsius) at which temperature it was possible to “trap” and obtain images of the smallest possible pieces (hexamers) of ice using a scanning tunnelling microscope (STM). The hexamer – the simplest and most basic “snow flake” – is composed of just six water molecules. Other ice nanoclusters containing seven, eight and nine molecules were also imaged.

On the difficulties of imaging these ice clusters, Prof Morgenstern said: “Scientists have long struggled to resolve single water molecules within ice clusters, because they are so vulnerable to damage induced by electrons – the very thing that creates the image. The high resolution could only be achieved by reducing the current to the smallest value technically possible.”

As well as performing experiments, the team used highly-accurate (‘first principles’) theoretical models to analyse how such a structure could form. Here the theory provided some surprising insights. In ice, water molecules usually bond to each other with equal strength but with the ice nanoclusters the team identified a pattern of alternating shorter and longer bonds between the water molecules. This pattern provided new information about the ability of water molecules to share their hydrogen bonds, revealing a hitherto unknown competition between the ability of water molecules to bind to a metal surface and simultaneously accept hydrogen bonds.

Dr Michaelides said, “We are all familiar with the freezing of water. It features prominently in our daily lives, from fridge freezers to winter snow. Despite all this, the question of how individual water molecules come together and give birth to ice crystals remains mysterious. Our research provides an insight into the most important and ubiquitous type of ice nucleation event, namely heterogeneous nucleation. State-of-the-art experimental and theoretical techniques allowed us to “watch” and accurately model what happens at very low temperatures.”

The research makes it possible to explain the ways in which water structures form on different substrates, such as transition metals and salt surfaces. It may also provide a new way of thinking about the structure of ice clusters that form on solid surfaces in general, opening the door for applications in a variety of fields as diverse as astronomy, electrochemistry, and energy research. It also takes us a step closer to understanding how water interacts with different aerosols and dust particles in the atmosphere, processes which drive cloud formation and have a large impact on the planet’s climate.

David Weston | alfa
Further information:
http://www.ucl.ac.uk

More articles from Physics and Astronomy:

nachricht Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center

nachricht A quantum entanglement between two physically separated ultra-cold atomic clouds
17.05.2018 | University of the Basque Country

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: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>