Molecules of hydrogen are difficult to steer with electric fields because of the symmetrical way that charges are distributed within them. But now researchers at ETH Zurich have found a clever technique to get a grip on the molecules. Their findings are reported in Physical Review Letters and highlighted in the September 14 issue of Physics (http://physics.aps.org).
Electric fields can easily manipulate electrically asymmetric molecules like water, but electric forces can't overcome thermal motions for highly symmetric molecules like H2. In the 1980s, researchers in search of a way to manipulate non-polar molecules proposed a trick: excite one of H2's two electrons into a high orbit, disrupting the molecule's symmetry. The far-flung electron feels the pull of the electric field and drags the rest of the molecule along, rendering H2 as manageable as a puppet on a string.
Now Stephen Hogan, Christian Seiler, and Frederic Merkt at ETH Zurich have made this idea reality by overcoming a key problem: an electron in an excited orbit usually reverts to its ground state long before researchers can take advantage of the molecule's maneuverability. They studied several excited orbits in detail, found the longest-lasting ones, and used lasers to select these special states from a group of hydrogen molecules. The newly manageable molecules could be slowed down and trapped for 50 microseconds, plenty of time for the team to study them in detail.
Size isn't the only thing that matters for data storage
Minute magnetic particles, whether bonded to plastic tape or coated onto a hard disk, are the basis of modern data storage. Information is encoded in the magnetic orientation of these nanoparticles, but particles can sometimes switch orientations spontaneously, which can potentially corrupt data. Now researchers from Lawrence Berkeley and Argonne National Laboratories report that this switching unfolds in a more complicated manner than was previously thought. Their work is published in Physical Review Letters and highlighted in the September 14 issue of Physics (http://physics.aps.org).
Scientists have long known that spin flipping becomes more likely as the size of a nanoparticle cluster dwindles. But Stefan Krause and his team discovered that this is not the end of the story. Flipping happens as a kind of chain reaction along a cluster, and the shape of a cluster can help or hinder this propagation. Manipulating the shape of a cluster and even inserting impurities can determine whether a switch is more or less likely to be triggered and propagate, potentially adding a new dimension of control to the design of magnetic devices.
Also in Physics this week:
Guenter Ahlers writes a Trends article in Physics (http://physics.aps.org) on how the unexplored details of convection could hold the key to understanding nature's most impressive phenomena, such as sunspots and patterns in the sun's photosphere.
About APS Physics
APS Physics (http://physics.aps.org) publishes expert written commentaries and highlights of papers appearing in the journals of the American Physical Society.
First users at European XFEL
21.09.2017 | European XFEL GmbH
Tiny lasers from a gallery of whispers
20.09.2017 | American Institute of Physics
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
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