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Category: particle physics – Page 373

Chemists change the bonds between atoms in a single molecule for the first time

A team of researchers from IBM Research Europe, Universidade de Santiago de Compostela and the University of Regensburg has changed the bonds between the atoms in a single molecule for the first time. In their paper published in the journal Science, the group describes their method and possible uses for it. Igor Alabugin and Chaowei Hu, have published a Perspective piece in the same journal issue outlining the work done by the team.

The current method for creating or molecular devices, as Alagugin and Chaowei note, is generally quite challenging—they liken it to dumping a box of Legos in a washing machine and hoping that some useful connections are made. In this new effort, the research team has made such work considerably easier by using a scanning tunneling microscope (STM) to break the bonds in a molecule and then to customize the molecule by creating new bonds—a chemistry first.

The work by the team involved placing a sample material into a and then using a very tiny amount of electricity to break specific bonds. More specifically, they began by pulling four atoms from the core of a tetracyclic to use as their starting molecule. They then moved the tip of the STM to a C-CI bond and then broke the bond with a jolt of electricity. Doing so to the other C-CI and C-C pairs resulted in the formation of a diradical, which left six electrons free for use in forming other bonds. In one test of creating a new molecule, the team then used the (and a dose of high voltage) to form diagonal C-C bonds, resulting in the creation of a bent alkyne. In another example, they applied a dose of low voltage to create a cyclobutadiene ring.

Physicists harness quantum ‘time reversal’ to measure vibrating atoms

The quantum vibrations in atoms hold a miniature world of information. If scientists can accurately measure these atomic oscillations, and how they evolve over time, they can hone the precision of atomic clocks as well as quantum sensors, which are systems of atoms whose fluctuations can indicate the presence of dark matter, a passing gravitational wave, or even new, unexpected phenomena.

A major hurdle in the path toward better quantum measurements is noise from the , which can easily overwhelm subtle atomic vibrations, making any changes to those vibrations devilishly hard to detect.

Now, MIT physicists have shown they can significantly amplify quantum changes in atomic vibrations, by putting the particles through two key processes: and time reversal.

Researchers reveal an unexpected feature of atomic nuclei when a ‘magic’ number of neutrons is reached

A curious thing happened when MIT researchers Adam Vernon and Ronald Garcia Ruiz, along an international team of scientists, recently performed an experiment in which a sensitive laser spectroscopy technique was used to measure how the nuclear electromagnetic properties of indium isotopes evolve when an extreme number of neutrons are added to the nucleus. These nuclei do not exist in nature, and once created, their lifetimes can be as short as a fraction of a second, so the team artificially created the nuclei using a particle accelerator at the CERN research facility in Switzerland. By using a combination of multiple lasers and an ion trap, the team isolated the isotopes of interest and performed precision measurements of atoms containing these exotic nuclei. In turn, it allowed the extraction of their nuclear properties.

Vernon, a postdoc in the Laboratory for Nuclear Science (LNS); Garcia Ruiz, an assistant professor of physics and LNS affiliate; and their colleagues achieved a surprising result. When measuring a with a certain “magic” number of neutrons—82—the of the nucleus exhibited a drastic change, and the properties of these very complex nuclei appear to be governed by just one of the protons of the nucleus.

“The new observation at 82 total neutrons changes this picture of the nucleus. We had to come up with new nuclear theories to explain the result,” says Vernon.

TRISO Particles: The Most Robust Nuclear Fuel on Earth

TRISO particles cannot melt in a reactor and can withstand extreme temperatures well beyond the threshold of current nuclear fuels.

There’s a lot of buzz around advanced nuclear.

These technologies are going to completely change the way we think about nuclear reactors.

More than 70 projects are underway in the United States with new designs that are expected to be more economical to build and operate.

New technique reveals interactions inside indium nucleus

An investigation into a neutron-rich isotope of indium using a cutting-edge nuclear physics technique has begun to unravel the mysteries of how single particles behave inside the nucleus.

We have known that a nucleus is comprised of protons, which give an element its atomic number, and neutrons since the early 1930s. But how an individual proton or neutron behaves inside the heart of an atom is still poorly understood. Now, an international collaboration including scientists from Canada, China, Finland, France, Germany, Poland, Sweden, Switzerland, the UK and US has taken a step closer to understanding these complex interactions.

Nuclear physics researchers often look at elements with so-called ‘magic numbers’ of protons or neutrons, which are exceptionally well bound and thus highly stable. However, to learn about nuclear structure, nuclides with one fewer proton are used, known as a single proton hole. By investigating the electronic transitions, researchers can study the atomic, hyperfine structure of individual particles due to the interactions between electrons and the nucleus. This gives clues as to the nucleus’ magnetic and electric characteristics, which can then give a complete picture of how all protons and neutrons are distributed and interact inside a nucleus.

Turning an arid desert into an unexpected breadbasket

How did the Arava, a punishingly hot and arid desert, become one of Israel’s breadbaskets? It’s a story of determination and thinking outside the box.

The discovery could inform the design of practical superconducting devices. When it comes to graphene, it appears that superconductivity runs in the family. Graphene is a single-atom-thin 2D material that can be produced by exfoliation from the same graphite that is found in pencil lead. The u.

MIT Physicists Discover a Family of “Magic” Superconducting Graphene Structures

The discovery could inform the design of practical superconducting devices.

When it comes to graphene.

Graphene is an allotrope of carbon in the form of a single layer of atoms in a two-dimensional hexagonal lattice in which one atom forms each vertex. It is the basic structural element of other allotropes of carbon, including graphite, charcoal, carbon nanotubes, and fullerenes. In proportion to its thickness, it is about 100 times stronger than the strongest steel.