Featured Research

from universities, journals, and other organizations

Researchers 'cage' water to see it change form

Date:
June 13, 2014
Source:
University of Southampton
Summary:
Scientists are using a pioneering method of ‘caging’ and cooling water molecules to study the change in orientation of the magnetic nuclei at the center of each hydrogen atom - a process which transforms the molecule from one form of water to another. By trapping water molecules in carbon spheres and cooling them, scientists have been able to follow the change in form (or isomer) of the molecules.

Scientists are using a pioneering method of 'caging' and cooling water molecules to study the change in orientation of the magnetic nuclei at the centre of each hydrogen atom -- a process which transforms the molecule from one form of water to another.

By trapping water molecules in carbon spheres and cooling them, scientists at the universities of Southampton, Nottingham and Columbia University in New York, have been able to follow the change in form (or isomer) of the molecules. The results of this work may one day help to enhance the diagnostic power of MRI scans.

Water molecules can exist as one of two isomers, depending on how the spins of their two hydrogen atoms are orientated: ortho, where the nuclear spins are parallel to one another, and para, where the spins are antiparallel. Scientists believe that any given molecule can transform from ortho- into para- spin states and vice versa, a process known as nuclear spin conversion.

"Currently, mechanisms for this conversion are not completely understood, nor how long it takes the molecules to transform from one spin isomer to the other," said Salvatore Mamone, a post-doctoral physicist at the University of Southampton and lead author on the JCP paper. "To study this, we had to figure out how to reduce the strong intermolecular interactions that are responsible for grouping of molecules and lowering the rotational mobility of the water molecules."

The answer was to isolate the water molecules from one-another by 'caging' them in fullerene (C60, also known as a buckyball) spheres.

Chemical reactions are used to open a hole in the spheres where water molecules can be injected, before the "cages" are closed, to form a complex referred to as H2O@C60. "At the end of this synthetic preparation nicknamed 'molecular surgery,' we find that 70 to 90 percent of the cages are filled, giving us a significant quantity of water molecules to examine," Mamone said. "Because the molecules are kept separate by the cages, there is a large rotational freedom that makes observation of the ortho and para isomers possible."

The fullerene cages prevent water molecules from freezing, meaning that the hydrogen atoms continue to spin and conversion is still able to occur.

In their experiment, the researchers quickly cooled the individual H2O@C60 samples from 50 Kelvin (minus 223 degrees Celsius) to 5 K (minus 268 degrees Celsius) and then monitored their NMR (Nuclear Magnetic Resonance) signal every few minutes over several days.

"As the observed NMR signal is proportional to the amount of ortho-water in the sample (para-water "NMR silent"), we can track the percentages of ortho and para isomers at any time and any temperature," Mamone explained. "At 50 K, we find that 75 percent of the water molecules are ortho, while at 5 K, they become almost 100 percent para. Therefore, we know that after the quick temperature jump, equilibrium is restored by conversion from ortho to para -- and we see that conversion in real time."

The research team now plans to study the roles of isomer concentrations and temperature in the conversion process, the conversion of para-water to ortho ('back conversion'), how to detect single ortho- and para-water molecules on surfaces, and spin isomers in other fullerene-caged molecules.


Story Source:

The above story is based on materials provided by University of Southampton. Note: Materials may be edited for content and length.


Cite This Page:

University of Southampton. "Researchers 'cage' water to see it change form." ScienceDaily. ScienceDaily, 13 June 2014. <www.sciencedaily.com/releases/2014/06/140613084425.htm>.
University of Southampton. (2014, June 13). Researchers 'cage' water to see it change form. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2014/06/140613084425.htm
University of Southampton. "Researchers 'cage' water to see it change form." ScienceDaily. www.sciencedaily.com/releases/2014/06/140613084425.htm (accessed July 29, 2014).

Share This




More Matter & Energy News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Newsy (July 28, 2014) Stanford University published its findings for a "pure" lithium ion battery that could have our everyday devices and electric cars running longer. Video provided by Newsy
Powered by NewsLook.com
The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins