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How a Single Chemical Bond Balances Cells Between Life and Death

With SLAC's X-ray laser and synchrotron, scientists measured exactly how much energy goes into keeping a crucial chemical bond from triggering a cell's death spiral.

New Efficient, Low-Temperature Catalyst for Converting Water and CO to Hydrogen Gas and CO2

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Study Sheds Light on How Bacterial Organelles Assemble

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A Single Electron's Tiny Leap Sets Off 'Molecular Sunscreen' Response

In experiments at the Department of Energy's SLAC National Accelerator Laboratory, scientists were able to see the first step of a process that protects a DNA building block called thymine from sun damage: When it's hit with ultraviolet light, a single electron jumps into a slightly higher orbit around the nucleus of a single oxygen atom.

Researchers Find New Mechanism for Genome Regulation

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The Rise of Giant Viruses

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Grasses: The Secrets Behind Their Success

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SLAC Experiment is First to Decipher Atomic Structure of an Intact Virus with an X-ray Laser

An international team of scientists has for the first time used an X-ray free-electron laser to unravel the structure of an intact virus particle on the atomic level. The method dramatically reduces the amount of virus material required, while also allowing the investigations to be carried out several times faster than before. This opens up entirely new research opportunities.

New Perspectives Into Arctic Cloud Phases

Teamwork provides insight into complicated cloud processes that are important to potential environmental changes in the Arctic.

Illuminating a Better Way to Calculate Excitation Energy

In a new study appearing this week in The Journal of Chemical Physics, researchers demonstrate a new method to calculate excitation energies. They used a new approach based on density functional methods, which use an atom-by-atom approach to calculate electronic interactions. By analyzing a benchmark set of small molecules and oligomers, their functional produced more accurate estimates of excitation energy compared to other commonly used density functionals, while requiring less computing power.


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Chicago Quantum Exchange to Create Technologically Transformative Ecosystem

The University of Chicago is collaborating with the U.S. Department of Energy's Argonne National Laboratory and Fermi National Accelerator Laboratory to launch an intellectual hub for advancing academic, industrial and governmental efforts in the science and engineering of quantum information.

Department of Energy Awards Six Research Contracts Totaling $258 Million to Accelerate U.S. Supercomputing Technology

Today U.S. Secretary of Energy Rick Perry announced that six leading U.S. technology companies will receive funding from the Department of Energy's Exascale Computing Project (ECP) as part of its new PathForward program, accelerating the research necessary to deploy the nation's first exascale supercomputers.

Cynthia Jenks Named Director of Argonne's Chemical Sciences and Engineering Division

Argonne has named Cynthia Jenks the next director of the laboratory's Chemical Sciences and Engineering Division. Jenks currently serves as the assistant director for scientific planning and the director of the Chemical and Biological Sciences Division at Ames Laboratory.

Argonne-Developed Technology for Producing Graphene Wins TechConnect National Innovation Award

A method that significantly cuts the time and cost needed to grow graphene has won a 2017 TechConnect National Innovation Award. This is the second year in a row that a team at Argonne's Center for Nanoscale Materials has received this award.

Honeywell UOP and Argonne Seek Research Collaborations in Catalysis Under Technologist in Residence Program

Researchers at Argonne are collaborating with Honeywell UOP scientists to explore innovative energy and chemicals production.

Follow the Fantastic Voyage of the ICARUS Neutrino Detector

The ICARUS neutrino detector, born at Gran Sasso National Lab in Italy and refurbished at CERN, will make its way across the sea to Fermilab this summer. Follow along using an interactive map online.

JSA Awards Graduate Fellowships for Research at Jefferson Lab

Jefferson Sciences Associates announced today the award of eight JSA/Jefferson Lab graduate fellowships. The doctoral students will use the fellowships to support their advanced studies at their universities and conduct research at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) - a U.S. Department of Energy nuclear physics laboratory managed and operated by JSA, a joint venture between SURA and PAE Applied Technologies.

Muon Magnet's Moment Has Arrived

On May 31, the 50-foot-wide superconducting electromagnet at the center of the Muon g-2 experiment saw its first beam of muon particles from Fermilab's accelerators, kicking off a three-year effort to measure just what happens to those particles when placed in a stunningly precise magnetic field. The answer could rewrite scientists' picture of the universe and how it works.

Seven Small Businesses to Collaborate with Argonne to Solve Technical Challenges

Seven small businesses have been selected to collaborate with researchers at Argonne to address technical challenges as part of DOE's Small Business Vouchers Program.

JSA Names Charles Perdrisat and Charles Sinclair as Co-Recipients of its 2017 Outstanding Nuclear Physicist Prize

Jefferson Science Associates, LLC, announced today that Charles Perdrisat and Charles Sinclair are the recipients of the 2017 Outstanding Nuclear Physicist Prize. The 2017 JSA Outstanding Nuclear Physicist Award is jointly awarded to Charles Perdrisat for his pioneering implementation of the polarization transfer technique to determine proton elastic form factors, and to Charles Sinclair for his crucial development of polarized electron beam technology, which made such measurements, and many others, possible.


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Oxygen: The Jekyll and Hyde of Biofuels

Scientists are devising ways to protect plants, biofuels and, ultimately, the atmosphere itself from damage caused by an element that sustains life on earth.

The Rise of Giant Viruses

Research reveals that giant viruses acquire genes piecemeal from others, with implications for bioenergy production and environmental cleanup.

Grasses: The Secrets Behind Their Success

Researchers find a grass gene affecting how plants manage water and carbon dioxide that could be useful to growing biofuel crops on marginal land.

New Perspectives Into Arctic Cloud Phases

Teamwork provides insight into complicated cloud processes that are important to potential environmental changes in the Arctic.

Mountaintop Plants and Soils to Become Out of Sync

Plants and soil microbes may be altered by climate warming at different rates and in different ways, meaning vital nutrient patterns could be misaligned.

If a Tree Falls in the Amazon

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Turning Waste into Fuels, Microbial Style

A newly discovered metabolic process linking different bacteria in a community could enhance bioenergy production.

Department of Energy Awards Six Research Contracts Totaling $258 Million to Accelerate U.S. Supercomputing Technology

Today U.S. Secretary of Energy Rick Perry announced that six leading U.S. technology companies will receive funding from the Department of Energy's Exascale Computing Project (ECP) as part of its new PathForward program, accelerating the research necessary to deploy the nation's first exascale supercomputers.

Electrifying Magnetism

Researchers create materials with controllable electrical and magnetic properties, even at room temperature.

One Step Closer to Practical Fast Charging Batteries

Novel electrode materials have designed pathways for electrons and ions during the charge/discharge cycle.


Water: Finding the Normal Within the Weird

Article ID: 666428

Released: 2016-12-13 15:05:43

Source Newsroom: Pacific Northwest National Laboratory

  • Credit: Courtesy of Wikimedia Commons

    Water is unlike other substances because its solid form — like this iceberg — is less dense than its liquid form — like this ocean. Scientists are studying other weird properties of water.

  • Caption A laser (red arrow) creates a tiny drop of supercooled water above ice, allowing scientists to use a method called IRAS (green arrows) to measure in nanoseconds how fast supercooled water turns back into ice.

RICHLAND, Wash. – Water has many unusual properties, such as its solid form, ice, being able to float in liquid water, and they get weirder below its freezing point. Supercooled water — below freezing but still a liquid — is notoriously difficult to study. Some researchers thought supercooled water behaved oddly within a particularly cold range, snapping from a liquid into a solid, instantaneously crystallizing at a particular temperature like something out of a Kurt Vonnegut novel.

Now, researchers have figured out a way to take snapshots of water freezing within that deeply supercooled range. And guess what? Water isn't as weird as it could be. Liquid water can exist all the way down, crystallizing into a solid more slowly as things get colder — as expected, but never all at once.

A team of researchers from the Department of Energy's Pacific Northwest National Laboratory reported the work in this week's Proceedings of the National Academy of Sciences Early Edition online. Although the results won't change the way you make your iced tea in the summer, it might help theorists flesh out their understanding of water and help atmospheric scientists better understand rain and clouds.

Most people know that ice floats on liquid water, but they might not be aware that water has a hard time forming a glass. A glass — like a window — is a solid in which the molecules are actually arranged as they would be in a liquid.

Take a bunch of oranges. Oranges jumbled loosely in a bag are like a liquid — the individual molecules can move around pretty freely. If you pack the oranges neatly in a box, you form a crystal. If you tighten the bag and stop the jumbled oranges from moving around but without arranging them neatly, you form a glass.

Glasses are great because they can hold contaminants — think a fly in amber, or nuclear waste in vitrified glass — whereas crystals kick out contaminants — freezing seawater is one way to desalinate it. To make a glass, researchers melt sand or another component until it is liquid. And then they cool it so fast it can't form a crystal before it solidifies.

But freeze bulk water fast and it does not form a glass. It rapidly becomes ice. To become glass, liquid water must be cooled to a deeply subzero temperature within microseconds — about 136 Kelvin (about minus 215 degrees F), a temperature common in outer space, where some expect glassy water to exist.

The range that has been difficult to study is slightly above that so-called glass transition temperature. Scientists don't know what's going on between about 160 and 235 K. (In real life, that's between the temperature on Mars's moon Phobos and Fairbanks, Alaska, in the depth of winter.) At the high end of that range (closer to 235 K, Fairbanks), water freezes from a supercooled liquid to a crystal in milliseconds, which is way too fast for current analytical techniques to study.

Scientists came up with a variety of ideas to explain what might be going on in that unexplored region. They wondered if the water would remain metastable — liquid but poised to start crystallizing at a moment's notice — all the way down to temperatures where it becomes a glass. Or if the liquid would become unstable somewhere warmer than that, around 228 K (a little warmer than the record lows at McMurdo Station in Antarctica), at which point it would spontaneously crystallize due to what physicists call a singularity. Also, something within that range might be happening that can help explain why water has a hard time forming a glass.

"There was a plethora of postulates but a paucity of data," said PNNL chemical physicist Bruce Kay.

"Our goal was to develop a new technique to rapidly heat and cool nanoscale supercooled water films," said PNNL physicist Greg Kimmel.

To get the data in that unmeasurable range, Kimmel and Kay worked with Yuntao Xu, a laser expert, and others at PNNL and developed a way to heat and cool water on nanosecond timescales with a laser. Using this method, the PNNL scientists measured how quickly the supercooled water converted into crystalline ice as the temperature decreased. The crystallization time dropped from nanoseconds near the highest temperatures to hours at 126 K. At no point, especially at 228 K, did the supercooled water snap into a crystal, ruling out the possibility of a singularity.

To look for the singularity from another angle, the researchers explored how fast the molecules of supercooled water could move, and how much that changed as it got colder. If the singularity existed, they would expect the water molecules to be unable to move at some point. From the freezing point down to the glassing point, the molecules moved slower and slower in a complex but continuous fashion. Overall, the relation between the temperature and how fast the molecules could move did not suggest a singularity at 228 K.

"We can probably take the singularity off the table," said PNNL's Kay.

Taken together, the results provide valuable insight into how water behaves.

"For example, in atmospheric chemistry, supercooled drops of water are found in clouds. There are questions about how long they persist," said PNNL's Kimmel.

This work was performed in EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science User Facility at PNNL. This work was supported by the Department of Energy Office of Science.

Reference: Yuntao Xu, Nikolay G. Petrik, R. Scott Smith, Bruce D. Kay and Greg A. Kimmel. The growth rate of crystalline ice and the diffusivity of supercooled water from 126 K to 262 K, Proc Natl Acad Sci U S A Early Edition, December 12, 2016, DOI: 10.1073/pnas.1611395114.