New research by scientists from the University of Southampton has found that water molecules react differently to electric fields, which could provide a new way to study spin isomers at the single-molecule level.
Water molecules exist in two forms or 'isomers', ortho and para, that have different nuclear spin states. In ortho-water, the nuclear spins are parallel to one another, and in para water, the spins are antiparallel. The conversion of ortho water into para-water and vice-versa is relevant to a broad range of scientific fields from nuclear magnetic resonance (NMR) to astrophysics.
While it is possible to separate ortho- and para-water molecules it is difficult to study them in bulk water because rapid proton exchange and hindered molecular rotation obscure the direct observation of the two spin isomers.
To help observe this transformation in bulk water, the Southampton research team confined single water molecules in C60 carbon cages or 'buckyballs' to produce supramolecular endofullerene H2O@C60. The yield of this chemical synthesis was improved dramatically by the team, allowing them to study bulk quantities of this substance.
The carbon cages prevent water molecules from freezing and keep them separate, so that they continue to rotate freely at very low temperatures, making it possible to study the conversion.
Since water has an electric dipole moment (a measure of the separation of positive and negative electrical charges), the researchers measured the dielectric constant of H2O@C60 at cryogenic temperatures and found that it decreases as water converts from ortho to para, in line with quantum theory and previous NMR studies.
Dr Benno Meier, Senior Research Fellow in Chemistry and lead author, says: "The bulk dielectric constant of H2O@C60 depends on the spin isomer composition of the encapsulated water molecules. The observed time-dependent change in the bulk dielectric constant at 5K, as encapsulated water converts from the ortho to the para isomer, is due to a change in molecular polarizibility on spin conversion."
"This work is a result of a long-standing and fruitful collaboration between Professors Malcolm Levitt and Richard Whitby, who have been studying the ortho to para conversion on a molecular level for several years."
The research, which is published in Nature Communications, was funded by the Engineering and Physical Sciences Research Council (EPSRC), European Research Council (ERC) and the Wolfson Foundation.
Glenn Harris | EurekAlert!
Superconductivity research reveals potential new state of matter
17.08.2017 | DOE/Los Alamos National Laboratory
Spray-on electric rainbows: Making safer electrochromic inks
17.08.2017 | Georgia Institute of Technology
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
17.08.2017 | Physics and Astronomy
17.08.2017 | Earth Sciences
17.08.2017 | Physics and Astronomy