Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers reveal behaviors of the tiniest water droplets

16.08.2012
UC San Diego, Emory U. team create new simulations on SDSC's 'Gordon' supercomputer

A new study by researchers at the University of California, San Diego, and Emory University has uncovered fundamental details about the hexamer structures that make up the tiniest droplets of water, the key component of life – and one that scientists still don't fully understand.

The research, recently published in The Journal of the American Chemical Society (JACS), provides a new interpretation for experimental measurements as well as a vital test for future studies of our most precious resource. Moreover, understanding the properties of water at the molecular level can ultimately have an impact on many areas of science, including the development of new drugs or advances in climate change research.

"About 60% of our bodies are made of water that effectively mediates all biological processes," said Francesco Paesani, one of the paper's corresponding authors who is an assistant professor in the Department of Chemistry and Biochemistry at UC San Diego and a computational researcher with the university's San Diego Supercomputer Center (SDSC). "Without water, proteins don't work and life as we know it wouldn't exist. Understanding the molecular properties of the hydrogen bond network of water is the key to understanding everything else that happens in water. And we still don't have a precise picture of the molecular structure of liquid water in different environments."

Researchers know that the unique properties of water are due to its capability of forming a highly flexible but still dense hydrogen bond network which adapts according to the surrounding environment. As described in the JACS paper, researchers have determined the relative populations of the different isomers of the water hexamer as they assemble into various configurations called 'cage', 'prism', and 'book'.

The water hexamer is considered the smallest drop of water because it is the smallest water cluster that is three dimensional, i.e., a cluster where the oxygen atoms of the molecules do not lie on the same plane. As such, it is the prototypical system for understanding the properties of the hydrogen bond dynamics in the condensed phases because of its direct connection with ice, as well as with the structural arrangements that occur in liquid water.

This system also allows scientists to better understand the structure and dynamics of water in its liquid state, which plays a central role in many phenomena of relevance to different areas of science, including physics, chemistry, biology, geology, and climate research. For example, the hydration structure around proteins affects their stability and function, water in the active sites of enzymes affects their catalytic power, and the behavior of water adsorbed on atmospheric particles drives the formation of clouds.

"Until now, experiments and calculations on small water clusters have agreed very well up to the pentamer (in chemistry, meaning molecules made of five monomers) but the energetic ordering of the low-lying isomers of the hexamer has always been controversial," said Paesani.

Added corresponding author Joel M. Bowman, with Emory University's Department of Chemistry and the Cherry L. Emerson Center for Scientific Computation: "Ours are the first simulations that use an accurate, full-dimensional representation of the molecular interactions and exact inclusion of nuclear quantum effects through state-of-the-art computational approaches. These allow us to accurately determine the stability of the different isomers over a wide range of temperatures ranging from 0 to 150 Kelvin, (almost minus 460 degrees to about minus 190 degrees Fahrenheit)."

While the prism isomer was identified as the global minimum-energy structure, the quantum simulations predicted that both the cage and prism isomers are present in nearly equal amounts at extremely low temperatures, researchers found. As the temperature increased, more cages, and then book structures, began to appear.

Researchers used SDSC's new data-intensive Gordon supercomputer as well as SDSC's Triton compute cluster to conduct the data-intensive simulations.

"Our simulations took full advantage of Gordon distributing the computations over thousands of processors," said Volodymyr Babin, a researcher with UC San Diego's Department of Chemistry and Biochemistry. "That kind of parallel efficiency would be hardly achievable on a commodity cluster. The scalability of our computational approach stems from the combination of a state-of-the-art simulation technique (replica-exchange) with path-integral molecular dynamics."

Babin said the team is currently working on extending this methodology to study the microscopic origins of the unusual properties of liquid water and ice aiming to assess quantitatively the role played by nuclear quantum effects in the topology of the water phase diagram. This project involves a huge number of data-intensive quantum chemistry computations that are only feasible on supercomputers of the same class as Gordon, he added.

The JACS paper is called "The Water Hexamer: Cage, Prism or Both. Full Dimensional Quantum Simulations Say Both," and also included Yimin Wang from Emory University, who developed the potential used in the simulations. The research was supported by the National Science Foundation (NSF) through grants CHE-1111364 and CHE-1038028, NSF award TG-CHE110009 for computing time on the Extreme Science and Engineering Discovery Environment (XSEDE), and awards from the CCI Center for Aerosol Impacts on Climate and the Environment.

UC San Diego News on the web at: http://ucsdnews.ucsd.edu

Jan Zverina | EurekAlert!
Further information:
http://www.sdsc.edu

More articles from Physics and Astronomy:

nachricht Seeing the quantum future... literally
16.01.2017 | University of Sydney

nachricht Airborne thermometer to measure Arctic temperatures
11.01.2017 | Moscow Institute of Physics and Technology

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: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>