Separation of para and ortho water
Not all water is equal—at least not at the molecular level. There are two versions of the water molecule, para and ortho water, in which the spin states of the hydrogen nuclei are different. In the journal Angewandte Chemie, German researchers have now reported the successful separation of the two forms.
Spin is a quantum mechanical value that can be visualized as the intrinsic angular momentum of a particle rotating around its own axis. A hydrogen nucleus (proton) can adopt two different states, comparable to rotation clockwise and counterclockwise.
In the case of water, the nuclear spins of the two—indistinguishable—protons can be combined in four different ways: one antisymmetric and three symmetric wavefunctions. Water adopting the antisymmetric wavefunction is called para water, whereas water adopting one of the symmetric ones is called ortho water. Because switching from one state to the other is “forbidden” due to quantum-mechanical symmetry rules, the two spin isomers cannot interconvert without external influences such as collisions.
A team at the Center for Free Electron Laser Science (DESY and University of Hamburg) led by Jochen Küpper and Daniel Horke has now successfully separated the two spin isomers and prepared isolated, highly pure samples of para and ortho water.
The challenge was to “freeze” the spin states by diluting single water molecules to such an extent that they could no longer collide with each other. To achieve this, the researchers use a noble gas high-pressure chamber charged with one droplet of water. When the chamber’s pulse valve is opened, the mixture shoots into a vacuum chamber at supersonic speeds, cooling rapidly due to the extremely fast expansion. This results in a focused beam of very cold water molecules that are so far from each other that they cannot induce a spin flip in each other.
For the separation, the researchers made use of the fact that para and ortho water molecules do not have the same quantum states. In a strong inhomogeneous electric field, the accelerated water molecules are deflected from their flight path by a different amount depending on their quantum state.
Possible applications for spin-pure water extend to many fields. Astrophysicists have determined that the ratio of ortho water to para water in interstellar ice is different from what is expected. Spin-pure water could enable revealing laboratory experiments. Techniques such as nuclear magnetic resonance spectroscopy (NMR) could benefit as their sensitivity could be increased by the use of para water in the hydration shells of proteins, improving the determination of their structure.
About the Author
Dr. Jochen Küpper is a team leader at DESY and Professor of Experimental Physics at the University of Hamburg. His research field comprises molecular physics and physical chemistry, focusing on the interconnection of structure, dynamics, and function of molecules. He already received several awards, including the Nernst-Haber-Bodenstein Award of the German Bunsen Society in 2009 and a Consolidator Grant „COMOTION“ of the European Research Council in 2013.
Author: Jochen Küpper, DESY, Hamburg (Germany), http://desy.cfel.de/cid/cmi/
Title: Separating Para and Ortho Water
Angewandte Chemie International Edition
Permalink to the original article: http://dx.doi.org/10.1002/anie.201405986
Jochen Küpper | Angewandte Chemie
Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy