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
Complete skin regeneration system of fish unraveled
24.04.2018 | Tokyo Institute of Technology
Scientists generate an atlas of the human genome using stem cells
24.04.2018 | The Hebrew University of Jerusalem
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
24.04.2018 | Life Sciences
24.04.2018 | Materials Sciences
24.04.2018 | Trade Fair News