From SLAC National Accelerator Lab: “Researchers reveal how enzyme motions catalyze reactions”

From SLAC National Accelerator Lab

December 16, 2019
Ali Sundermier

What they learned could lead to a better understanding of how antibiotics are broken down in the body, potentially leading to the development of more effective drugs.

This illustration shows how an enzyme moves and changes as it catalyzes complex reactions and breaks down organic compounds. (10.1073/pnas.1901864116)

In a time-resolved X-ray experiment, researchers uncovered, at atomic resolution and in real time, the previously unknown way that a microbial enzyme breaks down organic compounds.

The team, led by Mark Wilson at the University of Nebraska Lincoln (UNL) and Henry van den Bedem at the Department of Energy’s SLAC National Accelerator Laboratory (now at Atomwise Inc.), published their findings last week in the Proceedings of the National Academy of Sciences. What they learned about this enzyme, whose structure is similar to one that is implicated in neurodegenerative diseases such as Parkinson’s, could lead to a better understanding of how antibiotics are broken down by microbes and to the development of more effective drugs.

Previously, the researchers used SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) to obtain the structure of the enzyme at very low temperatures using X-ray crystallography.

SLAC/SSRL

In this study, Medhanjali Dasgupta, a UNL graduate student who was the study’s first author, used the Linac Coherent Light Source (LCLS), SLAC’s X-ray laser, to watch the enzyme and its substrate within the crystal move and change as it went through a full catalytic cycle at room temperature.

SLAC/LCLS

The scientists used special software, designed by van den Bedem, that is highly sensitive to identifying protein movement from X-ray crystallography data to interpret the results, revealing never-before-seen motions that play a key role in catalyzing complex reactions, such as breaking down antibiotics. Next, the researchers hope to use LCLS to obtain room temperature structures of other enzymes to get a better look at how the motions occurring within them help move along reactions.

SSRL and LCLS are DOE Office of Science user facilities. This work was funded by the DOE Office of Science and the National Institutes of Health, among other sources.

See the full article here .

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

SLAC/LCLS

SLAC/LCLS II projected view

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

From Tokyo Institute of Technology- “Nanoscience breakthrough: Probing particles smaller than a billionth of a meter”

From Tokyo Institute of Technology

December 16, 2019

Professor Kimihisa Yamamoto
Institute of Innovative Research,
Tokyo Institute of Technology
Email yamamoto@res.titech.ac.jp
Tel +81-45-924-5260

Contact
Public Relations Section, Tokyo Institute of Technology
Email media@jim.titech.ac.jp
Tel +81-3-5734-2975

Scientists at Tokyo Institute of Technology (Tokyo Tech) developed a new methodology that allows researchers to assess the chemical composition and structure of metallic particles with a diameter of only 0.5 to 2 nm. This breakthrough in analytical techniques will enable the development and application of minuscule materials in the fields of electronics, biomedicine, chemistry, and more.

Figure: A schematic diagram of the direct detection of subnano clusters.

Tin oxide SNCs finely prepared by a dendrimer template method are loaded on the thin silica shell layers of plasmonic amplifiers, such that the Raman signals of the SNCs are substantially enhanced to a detectable level. The strength of the electromagnetic fields generated due to the surface plasmon resonance properties of the Au or Ag nanoparticles decays exponentially with distance from the surface. Therefore, a rational interfacial design between the amplifiers and SNCs is the key to acquiring strong Raman signals.

The study and development of novel materials have enabled countless technological breakthroughs and are essential across most fields of science, from medicine and bioengineering to cutting-edge electronics. The rational design and analysis of innovative materials at nanoscopic scales allows us to push through the limits of previous devices and methodologies to reach unprecedented levels of efficiency and new capabilities. Such is the case for metal nanoparticles, which are currently in the spotlight of modern research because of their myriad potential applications. A recently developed synthesis method using dendrimer molecules as a template allows researchers to create metallic nanocrystals with diameters of 0.5 to 2 nm (billionths of a meter). These incredibly small particles, called “subnano clusters” (SNCs), have very distinctive properties, such as being excellent catalyzers for (electro)chemical reactions and exhibiting peculiar quantum phenomena that are very sensitive to changes in the number of constituent atoms of the clusters.

Unfortunately, the existing analytic methods for studying the structure of nanoscale materials and particles are not suitable for SNC detection. One such method, called Raman spectroscopy, consists of irradiating a sample with a laser and analyzing the resulting scattered spectra to obtain a molecular fingerprint or profile of the possible components of the material. Although traditional Raman spectroscopy and its variants have been invaluable tools for researchers, they still cannot be used for SNCs because of their low sensitivity. Therefore, a research team from Tokyo Tech, including Dr. Akiyoshi Kuzume, Prof. Kimihisa Yamamoto and colleagues, studied a way to enhance Raman spectroscopy measurements and make them competent for SNC analysis (Figure).

One particular type of Raman spectroscopy approach is called surface-enhanced Raman spectroscopy. In its more refined variant, gold and/or silver nanoparticles enclosed in an inert thin silica shell are added to the sample to amplify optical signals and thus increase the sensitivity of the technique. The research team first focused on theoretically determining their optimal size and composition, where 100-nm silver optical amplifiers (almost twice the size commonly used) can greatly amplify the signals of the SNCs adhered to the porous silica shell. “This spectroscopic technique selectively generates Raman signals of substances that are in close proximity to the surface of the optical amplifiers,” explains Prof. Yamamoto. To put these findings to test, they measured the Raman spectra of tin oxide SNCs to see if they could find an explanation in their structural or chemical composition for their inexplicably high catalytic activity in certain chemical reactions. By comparing their Raman measurements with structural simulations and theoretical analyses, they found new insights on the structure of the tin oxide SNCs, explaining the origin of atomicity-dependent specific catalytic activity of tin oxide SNCs.

The methodology employed in this research could have great impact on the development of better analytic techniques and subnanoscale science. “Detailed understanding of the physical and chemical nature of substances facilitates the rational design of subnanomaterials for practical applications. Highly sensitive spectroscopic methods will accelerate material innovation and promote subnanoscience as an interdisciplinary research field,” concludes Prof. Yamamoto. Breakthroughs such as the one presented by this research team will be essential for broadening the scope for the application of subnanomaterials in various fields including biosensors, electronics, and catalysts.

Reference
Authors :
Akiyoshi Kuzume1, Miyu Ozawa2, Yuansen Tang2, Yuki Yamada2, Naoki Haruta1, Kimihisa Yamamoto1,2
Title of original paper : Ultrahigh sensitive Raman spectroscopy for subnanoscience: Direct observation of tin oxide clusters
Journal : Science Advances, 5, eaax6455 (2019)

See the full article for other references with links.

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Tokyo Tech is the top national university for science and technology in Japan with a history spanning more than 130 years. Of the approximately 10,000 students at the Ookayama, Suzukakedai, and Tamachi Campuses, half are in their bachelor’s degree program while the other half are in master’s and doctoral degree programs. International students number 1,200. There are 1,200 faculty and 600 administrative and technical staff members.

In the 21st century, the role of science and technology universities has become increasingly important. Tokyo Tech continues to develop global leaders in the fields of science and technology, and contributes to the betterment of society through its research, focusing on solutions to global issues. The Institute’s long-term goal is to become the world’s leading science and technology university.

From D.O.E. Office of Science via Brookhaven National Lab: “The Big Questions: José Rodriguez on Catalysts”

Brookhaven National Lab

December 4, 2019
José Rodriguez

Distinguished Scientists Fellow José Rodriguez from Brookhaven Lab worked with fellow chemist Ping Liu to characterize structural and mechanistic details of a low-temperature catalyst for producing hydrogen gas from water and carbon monoxide.
Image courtesy of Brookhaven National Laboratory.

The Big Questions series features perspectives from the five recipients of the Department of Energy Office of Science’s 2019 Distinguished Scientists Fellows Award describing their research and what they plan to do with the award.

Contributing Author Credit: José Rodriguez is a senior chemist at Brookhaven National Laboratory.

How can we use some of the world’s brightest and strongest sources of synchrotron light to better understand the catalysts that speed up chemical reactions?

Catalysts reduce the energy needed to make a chemical reaction take place. They’re essential in industry, used for making everything from fabric to synthetic plants. Catalysts are used in the production of many chemicals and fuels.

Over the years, people have tried to understand how catalysts work in hopes of making them even better. To understand how a catalyst works, you need to see what happens at its active sites during chemical transformations. This is a very complex thing. You need a lot of tools to see how the catalyst changes over time, especially under harsh environmental conditions like high pressures and temperatures. Synchrotrons – incredibly powerful sources of light that produce X-rays – can provide a unique look into how these catalysts work.

When I first arrived at the Department of Energy’s Brookhaven National Laboratory (BNL) 29 years ago, scientists were for the first time seriously proposing the use of a synchrotron to study catalysts. At that time, there was a lot of activity in the National Synchrotron Light Source (NSLS), a DOE Office of Science user facility.

BNL NSLS

At the end of my job interview, the head of BNL’s Chemistry Department asked, “How much money do you need to do this kind of science?” I said, “This is a very complex science. I need $750,000.” As a physical inorganic chemist, $50,000 was a lot of research money for him. But despite the price tag, he looked at me and said, “Okay, we’ll see what we can do.” He called up the person at DOE in charge of the catalysis program and said, “The young man looks very promising; we want to go into this new area. He needs $750,000.”

With that funding, my team and I used NSLS to study catalysts in very controlled environments. We created these environments by putting the catalysts in specialized ultra-high vacuum chambers originally developed by NASA in the 1960s. After setting the inside of the chambers to the conditions we wanted, we put them in the synchrotron. The hard and soft X-rays from the synchrotron made it possible to study the structural, electronic, and chemical properties of the catalytic material as well as how those changed during the reaction process.

There is still a big interest in the DOE Office of Science in understanding these catalytic materials. Since then, the NSLS has been replaced by its successor NSLS-II [below], which is also a DOE Office of Science user facility. With NSLS-II, we can use a high-intensity beam to do ultra-fast measurements. Now, we can make in-situ measurements of samples with highly diluted elements in times as short as milliseconds (a thousandth of a second). With this speed, we can now monitor catalysts’ properties during reactions very quickly. In catalysis research, the faster you can go, the better.

With this fellowship, I’m going to expand the work we’re doing at the NSLS-II to better understand catalysts’ properties and how they change during reactions. While we’ve been working on this project for about five years, this new funding will help us move it forward. This work will involve not just the NSLS-II, but also researchers at BNL’s Center for Functional Nanomaterials (a DOE Office of Science user facility), the University of Kansas, Stony Brook University, and Columbia University. In the spirit of this fellowship, any equipment we develop will remain at the NSLS-II, where it will be available for the entire catalysis community to use.

I think this project has the potential to make a big contribution to the field and I appreciate the opportunity the DOE’s Office of Science has provided me to lead it.

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

BNL Center for Functional Nanomaterials

BNL NSLS-II

BNL NSLS II

BNL RHIC Campus

BNL/RHIC Star Detector

BNL RHIC PHENIX

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

From JHU HUB: “Copper could help unlock the clean-energy potential of hydrogen fuel cells”

From JHU HUB

11.1.19
Lisa Ercolano
Matthew Chin

Hydrogen fuel cells may someday power automobiles and trucks, offering a source of energy that’s free of carbon emissions and pollutants. But their potential has been limited thus far by the high cost and instability of the platinum-nickel catalyst needed to spark the chemical reaction that produces clean electricity.

Using experiments and computer simulations, materials scientists from Johns Hopkins University and the University of California, Los Angeles have taken a major leap toward making that future possible. Their study, published in Matter, sheds new light on a method of stabilizing catalysts by adding copper and provides details on why the method works.

Copper in the Periodic Table

The UCLA team was led by Yu Huang, a professor of materials science and engineering. The Hopkins team was led by Tim Mueller, assistant professor of materials science and engineering.

“The problem is that platinum-nickel catalysts, which are very promising for use in fuel cells, degrade over time as the nickel dissolves,” explains Mueller, whose research focuses on developing and applying computational methods to allow researchers to understand the real-world behavior of materials and to develop new materials for advanced technologies. “Professor Huang’s group discovered that adding copper to the catalysts helped reduce the amount of nickel dissolution, and our group helped them figure out why, which is important for people who want to build on this research.”

In experiments, the UCLA researchers found that introducing copper atoms into specially shaped nanoparticles of platinum-nickel resulted in durability that proved to be 40% better, in terms of catalyst efficiency, than those without copper. These new catalysts were very stable—that is, more transition metals were retained in the platinum-nickel-copper particles, despite the corrosive condition that could leach them out. They were also more efficient in catalyzing the chemical reaction, compared to alloys of platinum-nickel and commercially used platinum-carbon.

To figure out why this was happening, Mueller’s team at Hopkins devised a model based on experimental data and performed computer simulations that revealed how individual atoms moved around the nanoparticles in the type of environment that the catalysts would encounter in a fuel cell.

“We ran simulations of the particles, both with and without copper, to see how the addition of copper affected the degradation of the particles,” said Liang Cao, a Johns Hopkins postdoctoral scholar of materials science and engineering, and a co-lead author of the study. “We were able to track the particles’ evolution on an atomic scale, and our simulations indicated that the particles that contained copper were more stable because they initially had more platinum on the surface, which protected the nickel and copper atoms from dissolving.”

According to Huang, the new study is a milestone in understanding the “atomistic structure-function relations in nanoscale materials and opens the door to new design strategies for high-performing nanoscale catalysts.”

See the full article here .

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

About the Hub
We’ve been doing some thinking — quite a bit, actually — about all the things that go on at Johns Hopkins. Discovering the glue that holds the universe together, for example. Or unraveling the mysteries of Alzheimer’s disease. Or studying butterflies in flight to fine-tune the construction of aerial surveillance robots. Heady stuff, and a lot of it.

In fact, Johns Hopkins does so much, in so many places, that it’s hard to wrap your brain around it all. It’s too big, too disparate, too far-flung.

We created the Hub to be the news center for all this diverse, decentralized activity, a place where you can see what’s new, what’s important, what Johns Hopkins is up to that’s worth sharing. It’s where smart people (like you) can learn about all the smart stuff going on here.

At the Hub, you might read about cutting-edge cancer research or deep-trench diving vehicles or bionic arms. About the psychology of hoarders or the delicate work of restoring ancient manuscripts or the mad motor-skills brilliance of a guy who can solve a Rubik’s Cube in under eight seconds.

There’s no telling what you’ll find here because there’s no way of knowing what Johns Hopkins will do next. But when it happens, this is where you’ll find it.

The Johns Hopkins University opened in 1876, with the inauguration of its first president, Daniel Coit Gilman. “What are we aiming at?” Gilman asked in his installation address. “The encouragement of research … and the advancement of individual scholars, who by their excellence will advance the sciences they pursue, and the society where they dwell.”

The mission laid out by Gilman remains the university’s mission today, summed up in a simple but powerful restatement of Gilman’s own words: “Knowledge for the world.”

What Gilman created was a research university, dedicated to advancing both students’ knowledge and the state of human knowledge through research and scholarship. Gilman believed that teaching and research are interdependent, that success in one depends on success in the other. A modern university, he believed, must do both well. The realization of Gilman’s philosophy at Johns Hopkins, and at other institutions that later attracted Johns Hopkins-trained scholars, revolutionized higher education in America, leading to the research university system as it exists today.

From Stanford University: “Stanford researchers create new catalyst that can turn carbon dioxide into fuels”

From Stanford University

October 17, 2019
Andrew Myers

Aisulu Aitbekova, left, and Matteo Cargnello in front of the reactor where Aitbekova performed much of the experiments for this project. (Image credit: Mark Golden)

Imagine grabbing carbon dioxide from car exhaust pipes and other sources and turning this main greenhouse gas into fuels like natural gas or propane: a sustainability dream come true.

Several recent studies have shown some success in this conversion, but a novel approach from Stanford University engineers yields four times more ethane, propane and butane than existing methods that use similar processes. While not a climate cure-all, the advance could significantly reduce the near-term impact on global warming.

“One can imagine a carbon-neutral cycle that produces fuel from carbon dioxide and then burns it, creating new carbon dioxide that then gets turned back into fuel,” said Matteo Cargnello, an assistant professor of chemical engineering at Stanford who led the research, published in Angewandte Chemie.

Although the process is still just a lab-based prototype, the researchers expect it could be expanded enough to produce useable amounts of fuel. Much work remains, however, before average consumer will be able to purchase products based on such technologies. Next steps include trying to reduce harmful byproducts from these reactions, such as the toxic pollutant carbon monoxide. The group is also developing ways to make other beneficial products, not just fuels. One such product is olefins, which can be used in a number of industrial applications and are the main ingredients for plastics.

Two steps in one

Previous efforts to convert CO2 to fuel involved a two-step process. The first step reduces CO2 to carbon monoxide, then the second combines the CO with hydrogen to make hydrocarbon fuels. The simplest of these fuels is methane, but other fuels that can be produced include ethane, propane and butane. Ethane is a close relative of natural gas and can be used industrially to make ethylene, a precursor of plastics. Propane is commonly used to heat homes and power gas grills. Butane is a common fuel in lighters and camp stoves.

Cargnello thought completing both steps in a single reaction would be much more efficient, and set about creating a new catalyst that could simultaneously strip an oxygen molecule off of CO2 and combine it with hydrogen. (Catalysts induce chemical reactions without being used up in the reaction themselves.) The team succeeded by combining ruthenium and iron oxide nanoparticles into a catalyst.

“This nugget of ruthenium sits at the core and is encapsulated in an outer sheath of iron,” said Aisulu Aitbekova, a doctoral candidate in Cargnello’s lab and lead author of the paper. “This structure activates hydrocarbon formation from CO2. It improves the process start to finish.”

The team did not set out to create this core-shell structure but discovered it through collaboration with Simon Bare, distinguished staff scientist, and others at the SLAC National Accelerator Laboratory. SLAC’s sophisticated X-ray characterization technologies helped the researchers visualize and examine the structure of their new catalyst. Without this collaboration, Cargnello said they would not have discovered the optimal structure.

“That’s when we began to engineer this material directly in a core-shell configuration. Then we showed that once we do that, hydrocarbon yields improve tremendously,” Cargnello said. “It is something about the structure specifically that helps the reactions along.”

Cargnello thinks the two catalysts act in tag-team fashion to improve the synthesis. He suspects the ruthenium makes hydrogen chemically ready to bond with the carbon from CO2. The hydrogen then spills onto the iron shell, which makes the carbon dioxide more reactive.

When the group tested their catalyst in the lab, they found that the yield for fuels such as ethane, propane and butane was much higher than their previous catalyst. However, the group still faces a few challenges. They’d like to reduce the use of noble metals such as ruthenium, and optimize the catalyst so that it can selectively make only specific fuels.

See the full article here .

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

Stanford University campus. No image credit

Stanford University

Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

From SLAC National Accelerator Lab: “Study shows a much cheaper catalyst can generate hydrogen in a commercial device”

From SLAC National Accelerator Lab

October 14, 2019
Glennda Chui
(650) 926-4897
glennda@slac.stanford.edu

Replacing today’s expensive catalysts could bring down the cost of producing the gas for fuel, fertilizer and clean energy storage.

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have shown for the first time that a cheap catalyst can split water and generate hydrogen gas for hours on end in the harsh environment of a commercial device.

The electrolyzer technology, which is based on a polymer electrolyte membrane (PEM), has potential for large-scale hydrogen production powered by renewable energy, but it has been held back in part by the high cost of the precious metal catalysts, like platinum and iridium, needed to boost the efficiency of the chemical reactions.

This study points the way toward a cheaper solution, the researchers reported today in Nature Nanotechnology.

(Greg Stewart/SLAC National Accelerator Laboratory)

“Hydrogen gas is a massively important industrial chemical for making fuel and fertilizer, among other things,” said Thomas Jaramillo, director of the SUNCAT Center for Interface Science and Catalysis, who led the research team. “It’s also a clean, high-energy-content molecule that can be used in fuel cells or to store energy generated by variable power sources like solar and wind. But most of the hydrogen produced today is made with fossil fuels, adding to the level of CO2 in the atmosphere. We need a cost-effective way to produce it with clean energy.”

From pricey metal to cheap, abundant materials

There’s been extensive work over the years to develop alternatives to precious metal catalysts for PEM systems. Many have been shown to work in a laboratory setting, but Jaramillo said that to his knowledge this is the first to demonstrate high performance in a commercial electrolyzer. The device was manufactured by a PEM electrolysis research site and factory in Connecticut for Nel Hydrogen, the world’s oldest and biggest manufacturer of electrolyzer equipment.

A commercial electrolyzer used in the experiments. Electrodes sprayed with catalyst powder are stacked inside the central metal plates and compressed with bolts and washers. Water flows in through a tube on the right, and hydrogen and oxygen gases flow out through tubes at left. (Nel Hydrogen)

Electrolysis works much like a battery in reverse: Rather than generating electricity, it uses electrical current to split water into hydrogen and oxygen. The reactions that generate hydrogen and oxygen gas take place on different electrodes using different precious metal catalysts. In this case, the Nel Hydrogen team replaced the platinum catalyst on the hydrogen-generating side with a catalyst consisting of cobalt phosphide nanoparticles deposited on carbon to form a fine black powder, which was produced by the researchers at SLAC and Stanford. Like other catalysts, it brings other chemicals together and encourages them to react.

The cobalt phosphide catalyst operated extremely well for the entire duration of the test, more than 1,700 hours – an indication that it may be hardy enough for everyday use in reactions that can take place at elevated temperatures, pressures and current densities and in extremely acidic conditions over extended lengths of time, said McKenzie Hubert, a graduate student in Jaramillo’s group who led the experiments with Laurie King, a SUNCAT research engineer who has since joined the faculty of Manchester Metropolitan University.

Stanford graduate student McKenzie Hubert with equipment used to test a cheap alternative to an expensive catalyst in the lab. A team led by Thomas Jaramillo, director of the SUNCAT center at SLAC and Stanford, went on to show for the first time that this cheap material could achieve high performance in a commercial electrolyzer. (Jacqueline Orrell/SLAC National Accelerator Laboratory)

Stanford graduate student McKenzie Hubert watches a catalyst produce bubbles of hydrogen in a small, lab-scale electrolyzer. The catalyst, cobalt phosphide, is much cheaper than the platinum catalyst used today and could reduce the cost of a process for making hydrogen – an important fuel and industrial chemical – on a large scale with clean, renewable energy. (Jacqueline Orrell/SLAC National Accelerator Laboratory)

“Our group has been studying this catalyst and related materials for a while,” Hubert said, “and we took it from a fundamental lab-scale, experimental stage through testing it under industrial operating conditions, where you need to cover a much larger surface area with the catalyst and it has to function under much more challenging conditions.”

One of the most important elements of the study was scaling up the production of the cobalt phosphide catalyst while keeping it very uniform – a process that involved synthesizing the starting material at the lab bench, grinding with a mortar and pestle, baking in a furnace and finally turning the fine black powder into an ink that could be sprayed onto sheets of porous carbon paper. The resulting large-format electrodes were loaded into the electrolyzer for the hydrogen production tests.

Producing hydrogen gas at scale

While the electrolyzer development was funded by the Defense Department, which is interested in the oxygen-generating side of electrolysis for use in submarines, Jaramillo said the work also aligns with the goals of DOE’s H2@Scale initiative, which brings DOE labs and industry together to advance the affordable production, transport, storage and use of hydrogen for a number of applications. The fundamental catalyst research was funded by the DOE Office of Science.

(Greg Stewart/SLAC National Accelerator Laboratory)

Katherine Ayers, vice president for research and development at Nel and a co-author of the paper, said, “Working with Tom gave us an opportunity to see whether these catalysts could be stable for a long time and gave us a chance to see how their performance compared to that of platinum.

“The performance of the cobalt phosphide catalyst needs to get a little bit better, and its synthesis would need to be scaled up,” she said. “But I was quite surprised at how stable these materials were. Even though their efficiency in generating hydrogen was lower than platinum’s, it was constant. A lot of things would degrade in that environment.”

While the platinum catalyst represents only about 8 percent of the total cost of manufacturing hydrogen with PEM, the fact that the market for the precious metal is so volatile, with prices swinging up and down, could hold back development of the technology, Ayers said. Reducing and stabilizing that cost will become increasingly important as other aspects of PEM electrolysis are improved to meet the increasing demand for hydrogen in fuel cells and other applications.

SUNCAT is a partnership between SLAC and the Stanford School of Engineering. Funding for this study came from a Small Business Innovation Research (SBIR) grant from the Department of Defense. Funding for fundamental catalyst development at SUNCAT, which provided the platform for this research, is provided by the DOE Office of Science.

See the full article here .

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

SLAC/LCLS

SLAC/LCLS II projected view

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

From MIT News: “A new mathematical approach to understanding zeolites”

From MIT News

October 7, 2019
David L. Chandler

Traditional structure-based representations of the many forms of zeolites, some of which are illustrated here, provide little guidance as to how they can convert to other forms, but a new graph-based system does a much better job. Illustrations courtesy of the researchers.

Study of minerals widely used in industrial processes could lead to discovery of new materials for catalysis and filtering.

Zeolites are a class of natural or manufactured minerals with a sponge-like structure, riddled with tiny pores that make them useful as catalysts or ultrafine filters. But of the millions of zeolite compositions that are theoretically possible, so far only about 248 have ever been discovered or made. Now, research from MIT helps explain why only this small subset has been found, and could help scientists find or produce more zeolites with desired properties.

The new findings are being reported this week in the journal Nature Materials, in a paper by MIT graduate students Daniel Schwalbe-Koda and Zach Jensen, and professors Elsa Olivetti and Rafael Gomez-Bombarelli.

Previous attempts to figure out why only this small group of possible zeolite compositions has been identified, and to explain why certain types of zeolites can be transformed into specific other types, have failed to come up with a theory that matches the observed data. Now, the MIT team has developed a mathematical approach to describing the different molecular structures. The approach is based on graph theory, which can predict which pairs of zeolite types can be transformed from one to the other.

This could be an important step toward finding ways of making zeolites tailored for specific purposes. It could also lead to new pathways for production, since it predicts certain transformations that have not been previously observed. And, it suggests the possibility of producing zeolites that have never been seen before, since some of the predicted pairings would lead to transformations into new types of zeolite structures.

Interzeolite tranformations

Zeolites are widely used today in applications as varied as catalyzing the “cracking” of petroleum in refineries and absorbing odors as components in cat litterbox filler. Even more applications may become possible if researchers can create new types of zeolites, for example with pore sizes suited to specific types of filtration.

All kinds of zeolites are silicate minerals, similar in chemical composition to quartz. In fact, over geological timescales, they will all eventually turn into quartz — a much denser form of the mineral — explains Gomez-Bombarelli, who is the Toyota Assistant Professor in Materials Processing. But in the meantime, they are in a “metastable” form, which can sometimes be transformed into a different metastable form by applying heat or pressure or both. Some of these transformations are well-known and already used to produce desired zeolite varieties from more readily available natural forms.

Currently, many zeolites are produced by using chemical compounds known as OSDAs (organic structure-directing agents), which provide a kind of template for their crystallization. But Gomez-Bombarelli says that if instead they can be produced through the transformation of another, readily available form of zeolite, “that’s really exciting. If we don’t need to use OSDAs, then it’s much cheaper [to produce the material].The organic material is pricey. Anything we can make to avoid the organics gets us closer to industrial-scale production.”

Traditional chemical modeling of the structure of different zeolite compounds, researchers have found, provides no real clue to finding the pairs of zeolites that can readily transform from one to the other. Compounds that appear structurally similar sometimes are not subject to such transformations, and other pairs that are quite dissimilar turn out to easily interchange. To guide their research, the team used an artificial intelligence system previously developed by the Olivetti group to “read” more than 70,000 research papers on zeolites and select those that specifically identify interzeolite transformations. They then studied those pairs in detail to try to identify common characteristics.

What they found was that a topological description based on graph theory, rather than traditional structural modeling, clearly identified the relevant pairings. These graph-based descriptions, based on the number and locations of chemical bonds in the solids rather than their actual physical arrangement, showed that all the known pairings had nearly identical graphs. No such identical graphs were found among pairs that were not subject to transformation.

The finding revealed a few previously unknown pairings, some of which turned out to match with preliminary laboratory observations that had not previously been identified as such, thus helping to validate the new model. The system also was successful at predicting which forms of zeolites can intergrow — forming combinations of two types that are interleaved like the fingers on two clasped hands. Such combinations are also commercially useful, for example for sequential catalysis steps using different zeolite materials.

Ripe for further research

The new findings might also help explain why many of the theoretically possible zeolite formations don’t seem to actually exist. Since some forms readily transform into others, it may be that some of them transform so quickly that they are never observed on their own. Screening using the graph-based approach may reveal some of these unknown pairings and show why those short-lived forms are not seen.

Some zeolites, according to the graph model, “have no hypothetical partners with the same graph, so it doesn’t make sense to try to transform them, but some have thousands of partners” and thus are ripe for further research, Gomez-Bombarelli says.

In principle, the new findings could lead to the development of a variety of new catalysts, tuned to the exact chemical reactions they are intended to promote. Gomez-Bombarelli says that almost any desired reaction could hypothetically find an appropriate zeolite material to promote it.

“Experimentalists are very excited to find a language to describe their transformations that is predictive,” he says.

This work is “a major advancement in the understanding of interzeolite transformations, which has become an increasingly important topic owing to the potential for using these processes to improve the efficiency and economics of commercial zeolite production,” says Jeffrey Rimer, an associate professor of chemical and biomolecular engineering at the University of Houston, who was not involved in this research.

Manuel Moliner, a tenured scientist at the Technical University of Valencia, in Spain, who also was not connected to this research, says: “Understanding the pairs involved in particular interzeolite transformations, considering not only known zeolites but also hundreds of hypothetical zeolites that have not ever been synthesized, opens extraordinary practical opportunities to rationalize and direct the synthesis of target zeolites with potential interest as industrial catalysts.”

See the full article here .

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

From SLAC National Accelerator Lab: “Plastics, fuels and chemical feedstocks from CO2? They’re working on it.”

From SLAC National Accelerator Lab

September 9, 2019
Glennda Chui

Researchers at Stanford and SLAC are working on ways to convert waste carbon dioxide (CO2) into chemical feedstocks and fuels, turning a potent greenhouse gas into valuable products. The process is called electrochemical conversion. When powered by renewable energy sources (far left), it could reduce levels of carbon dioxide in the air and store energy from these intermittent sources in a form that can be used any time. (Greg Stewart/SLAC National Accelerator Laboratory)

One way to reduce the level of carbon dioxide in the atmosphere, which is now at its highest point in 800,000 years, would be to capture the potent greenhouse gas from the smokestacks of factories and power plants and use renewable energy to turn it into things we need, says Thomas Jaramillo.

As director of SUNCAT Center for Interface Science and Catalysis, a joint institute of Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory, he’s in a position to help make that happen.

A major focus of SUNCAT research is finding ways to transform CO2 into chemicals, fuels, and other products, from methanol to plastics, detergents and synthetic natural gas. The production of these chemicals and materials from fossil fuel ingredients now accounts for 10% of global carbon emissions; the production of gasoline, diesel, and jet fuel accounts for much, much more.

“We have already emitted too much CO2, and we’re on track to continue emitting it for years, since 80% of the energy consumed worldwide today comes from fossil fuels,” says Stephanie Nitopi, whose SUNCAT research is the basis of her newly acquired Stanford PhD.

“You could capture CO2 from smokestacks and store it underground,” she says. “That’s one technology currently in play. An alternative is to use it as a feedstock to make fuels, plastics, and specialty chemicals, which shifts the financial paradigm. Waste CO2 emissions now become something you can recycle into valuable products, providing a new incentive to reduce the amount of CO2 released into the atmosphere. That’s a win-win.”

We asked Nitopi, Jaramillo, SUNCAT staff scientist Christopher Hahn and postdoctoral researcher Lei Wang to tell us what they’re working on and why it matters.

Q. First the basics: How do you convert CO2 into these other products?

Tom: It’s essentially a form of artificial photosynthesis, which is why DOE’s Joint Center for Artificial Photosynthesis funds our work. Plants use solar energy to convert CO2 from the air into carbon in their tissues. Similarly, we want to develop technologies that use renewable energy, like solar or wind, to convert CO2 from industrial emissions into carbon-based products.

Chris: One way to do this is called electrochemical CO2 reduction, where you bubble CO2 gas up through water and it reacts with the water on the surface of a copper-based electrode. The copper acts as a catalyst, bringing the chemical ingredients together in a way that encourages them to react. Put very simply, the initial reaction strips an oxygen atom from CO2 to form carbon monoxide, or CO, which is an important industrial chemical in its own right. Then other electrochemical reactions turn CO into important molecules such as alcohols, fuels and other things.

Today this process requires a copper-based catalyst. It’s the only one known to do the job. But these reactions can produce numerous products, and separating out the one you want is costly, so we need to identify new catalysts that are able to guide the reaction toward making only the desired product.

How so?

Lei: When it comes to improving a catalyst’s performance, one of the key things we look at is how to make them more selective, so they generate just one product and nothing else. About 90 percent of fuel and chemical manufacturing depends on catalysts, and getting rid of unwanted byproducts is a big part of the cost.

We also look at how to make catalysts more efficient by increasing their surface area, so there are a lot more places in a given volume of material where reactions can occur simultaneously. This increases the production rate.

Recently we discovered something surprising [Nature Catalysis]: When we increased the surface area of a copper-based catalyst by forming it into a flaky “nanoflower” shape, it made the reaction both more efficient and more selective. In fact, it produced virtually no byproduct hydrogen gas that we could measure. So this could offer a way to tune reactions to make them more selective and cost-competitive.

Stephanie: This was so surprising that we decided to revisit all the research we could find [Chem. Rev.] on catalyzing electrochemical CO2 conversion with copper, and the many ways people have tried to understand and fine-tune the process, using both theory and experiments, going back four decades. There’s been an explosion of research on this – about 60 papers had been published as of 2006, versus more than 430 out there today – and analyzing all the studies with our collaborators at the Technical University of Denmark took two years.

We were trying to figure out what makes copper special, why it’s the only catalyst that can make some of these interesting products, and how we can make it even more efficient and selective – what techniques have actually pushed the needle forward? We also offered our perspectives on promising research directions.

One of our conclusions confirms the results of the earlier study: The copper catalyst’s surface area can be used to improve both the selectivity and overall efficiency of reactions. So this is well worth considering as a chemical production strategy.

Does this approach have other benefits?

Tom: Absolutely. If we use clean, renewable energy, like wind or solar, to power the controlled conversion of waste CO2 to a wide range of other products, this could actually draw down levels of CO2 in the atmosphere, which we will need to do to stave off the worst effects of global climate change.

Chris: And when we use renewable energy to convert CO2 to fuels, we’re storing the variable energy from those renewables in a form that can be used any time. In addition, with the right catalyst, these reactions could take place at close to room temperature, instead of the high temperatures and pressures often needed today, making them much more energy efficient.

How close are we to making it happen?

Tom: Chris and I explored this question in a recent Perspective article in Science, written with researchers from the University of Toronto and TOTAL American Services, which is an oil and gas exploration and production services firm.

We concluded that renewable energy prices would have to fall below 4 cents per kilowatt hour, and systems would need to convert incoming electricity to chemical products with at least 60% efficiency, to make the approach economically competitive with today’s methods.

Chris: This switch couldn’t happen all at once; the chemical industry is too big and complex for that. So one approach would be to start with making high-value, high-volume products like ethylene, which is used to make alcohols, polyester, antifreeze, plastics and synthetic rubber. It’s a $230 billion global market today. Switching from fossil fuels to CO2 as a starting ingredient for ethylene in a process powered by renewables could potentially save the equivalent of about 860 million metric tons of CO2 emissions per year.

The same step-by-step approach applies to sources of CO2. Industry could initially use relatively pure CO2 emissions from cement plants, breweries or distilleries, for instance, and this would have the side benefit of decentralizing manufacturing. Every country could provide for itself, develop the technology it needs, and give its people a better quality of life.

Tom: Once you enter certain markets and start scaling up the technology, you can attack other products that are tougher to make competitively today. What this paper concludes is that these new processes have a chance to change the world.

See the full article here .

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

SLAC/LCLS

SLAC/LCLS II projected view

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

From SLAC National Accelerator Lab: “Capturing the behavior of single-atom catalysts on the move”

From SLAC National Accelerator Lab

April 23, 2019
Glennda Chui

A new study precisely controlled the attachment of platinum atoms (white balls) to a titanium dioxide surface (latticework of red and blue balls). It found that their positions varied from being deeply embedded in the surface (lower left) to standing almost free of the surface (upper right). This change in position affected the atoms’ ability to catalyze a chemical reaction that converts carbon monoxide to carbon dioxide (upper right). (Greg Stewart, SLAC National Accelerator Laboratory)

Scientists are excited by the prospect of stripping catalysts down to single atoms. Attached by the millions to a supporting surface, they could offer the ultimate in speed and specificity.

Now researchers have taken an important step toward understanding single-atom catalysts by deliberately tweaking how they’re attached to the surfaces that support them – in this case the surfaces of nanoparticles. They attached one platinum atom to each nanoparticle and observed how changing the chemistry of the particle’s surface and the nature of the attachment affected how keen the atom was to catalyze reactions.

Key experiments for the study took place at the Department of Energy’s SLAC National Accelerator Laboratory, and the results were reported in Nature Materials yesterday.

“We believe this is the first time the reactivity of a metallic single-atom catalyst has been traced to a specific way of attaching it to a particular supporting structure. This study is also unique in systematically controlling that attachment,” said Simon R. Bare, a distinguished staff scientist at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) and a co-author of the study.

SLAC/SSRL

“This is an important scientific breakthrough, and understanding on a fundamental level how the structure relates to the reactivity will ultimately allow us to design catalysts to be much more efficient. There is a huge number of people working on this problem.”

Harsh treatment, good results

Bare and other SLAC scientists were part of a previous study at SSRL [Nature Catalysis] that found that individual iridium atoms could catalyze a particular reaction up to 25 times more efficiently than the iridium nanoparticles used today, which contain 50 to 100 atoms.

This latest study was led by Associate Professor Phillip Christopher of the University of California, Santa Barbara. It looked at individual atoms of platinum that were attached to separate nanoparticles of titanium dioxide in his lab. While this approach would probably not be practical in a chemical plant or in your car’s catalytic converter, it did give the research team exquisitely fine control of where the atoms were placed and of the environment immediately around them, Bare said.

Researchers gave the nanoparticles chemical treatments – either harsh or mild – and used SSRL’s X-rays to observe how those treatments changed where and how the platinum atoms attached to the surface.

Meanwhile, scientists at the University of California, Irvine directly observed the attachments and positions of the platinum atoms with electron microscopes, and researchers at UC-Santa Barbara measured how active the platinum atoms were in catalyzing reactions.

Breaking through the surface

A platinum atom has six binding sites where it can hook up with other atoms. In untreated nanoparticles, the atoms were buried in the surface and firmly bound to six oxygen atoms each; they had no free binding sites that could grab other atoms and start a catalytic reaction.

In mildly treated particles, the platinum atoms emerged from the surface and were bound to just four oxygen atoms apiece, leaving them two free binding sites and the potential for more catalytic activity.

And in harshly treated particles, the atoms clung to the surface by only two bonds, leaving four binding sites free. When the researchers tested the ability of the variously treated nanoparticles to catalyze a reaction where carbon monoxide combines with oxygen to form carbon dioxide – the same reaction that takes place in a car’s catalytic converter – this one came out on top, Bare said, with five times greater activity than the others.

“While this study shows the importance of understanding the dynamic nature of catalysts,” Christopher said, “the next challenge will be to translate the findings to industrially relevant systems.”

SSRL is a DOE Office of Science user facility. The changing positions of the platinum atoms on the particle surfaces were imaged and observed with transmission electron microscopy using state-of-the-art facilities recently established at the Irvine Materials Research Institute (IMRI) at UC-Irvine. Detailed experimental insights obtained in the study were correlated with predictions made by theorists at the University of Milano-Bicocca in Italy.

See the full article here .

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

SLAC/LCLS

SLAC/LCLS II projected view

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

From SLAC National Accelerator Lab: “SLAC’s high-speed ‘electron camera’ films molecular movie in HD”

From SLAC National Accelerator Lab

April 15, 2019

Manuel Gnida
mgnida@slac.stanford.edu
(650) 926-2632

This illustration shows snapshots of the light-triggered transition of the ring-shaped 1,3-cyclohexadiene (CHD) molecule (background) to its stretched-out 1,3,5-hexatriene (HT) form (foreground). The snapshots were taken with SLAC’s high-speed “electron camera” – an instrument for ultrafast electron diffraction (UED). (Greg Stewart/SLAC National Accelerator Laboratory)

With an extremely fast “electron camera” at the Department of Energy’s SLAC National Accelerator Laboratory, researchers have made the first high-definition “movie” of ring-shaped molecules breaking open in response to light. The results could further our understanding of similar reactions with vital roles in chemistry, such as the production of vitamin D in our bodies.

Visualization of a molecular movie made with SLAC’s electron camera, in which researchers have captured in atomic detail how a ring-shaped molecule opens up in the first 800 millionths of a billionth of a second after being hit by a laser flash. Ring-opening reactions like this one play important roles in chemistry, such as the light-driven synthesis of vitamin D in our bodies. (Thomas Wolf/PULSE Institute)

A previous molecular movie of the same reaction, produced with SLAC’s Linac Coherent Light Source (LCLS) X-ray laser, for the first time recorded the large structural changes during the reaction.

This video describes how the Linac Coherent Light Source, an X-ray free-electron laser at SLAC National Accelerator Laboratory, provided the first direct measurements of how a ring-shaped gas molecule unravels in the millionths of a billionth of a second after it is split open by light. The measurements were compiled in sequence to form the basis for computer animations showing molecular motion. (SLAC National Accelerator Laboratory)

Now, making use of the lab’s ultrafast electron diffraction (UED) instrument, these new results provide high-resolution details – showing, for instance, how a bond in the ring breaks and atoms jiggle around for extended periods of time.

August 5, 2015- With SLAC’s new apparatus for ultrafast electron diffraction – one of the world’s fastest “electron cameras” – researchers can study motions in materials that take place in less than 100 quadrillionths of a second. A pulsed electron beam is created by shining laser pulses on a metal photocathode. The beam gets accelerated by a radiofrequency field and focused by a magnetic lens. Then it travels through a sample and scatters off the sample’s atomic nuclei and electrons, creating a diffraction image on a detector. Changes in these diffraction images over time are used to reconstruct ultrafast motions of the sample’s interior structure. (SLAC National Accelerator Laboratory)

“The details of this ring-opening reaction have now been settled,” said Thomas Wolf, a scientist at the Stanford Pulse Institute of SLAC and Stanford University and leader of the research team. “The fact that we can now directly measure changes in bond distances during chemical reactions allows us to ask new questions about fundamental processes stimulated by light.”

SLAC scientist Mike Minitti, who was involved in both studies, said, “The results demonstrate how our unique instruments for studying ultrafast processes complement each other. Where LCLS excels in capturing snapshots with extremely fast shutter speeds of only a few femtoseconds, or millionths of a billionth of a second, UED cranks up the spatial resolution of these snapshots. This is a great result, and the studies validate one another’s findings, which is important when making use of entirely new measurement tools.”

LCLS Director Mike Dunne said, “We’re now making SLAC’s UED instrument available to the broad scientific community, in addition to enhancing the extraordinary capabilities of LCLS by doubling its energy reach and transforming its repetition rate. The combination of both tools uniquely positions us to enable the best possible studies of fundamental processes on ultrasmall and ultrafast scales.”

The team reported their results today in Nature Chemistry.

Molecular movie in HD

This particular reaction has been studied many times before: When a ring-shaped molecule called 1,3-cyclohexadiene (CHD) absorbs light, a bond breaks and the molecule unfolds to form the almost linear molecule known as 1,3,5-hexatriene (HT). The process is a textbook example of ring-opening reactions and serves as a simplified model for studying light-driven processes during vitamin D synthesis.

In 2015, researchers studied the reaction with LCLS, which resulted in the first detailed molecular movie of its kind and revealed how the molecule changed from a ring to a cigar-like shape after it was struck by a laser flash. The snapshots, which initially had limited spatial resolution, were brought further into focus through computer simulations.

Researchers created the first atomic-resolution movie of the ring-opening reaction of 1,3-cyclohexadiene (CHD) with an “electron camera” called UED. Bottom: The UED electron beam accurately measures the distances between pairs of atoms in the CHD molecule as the reaction proceeds. The distance between each pair is represented by a colored line in the graph. Variations in the distances as the molecule changes shape represent the molecular movie. Top: Visualization of the molecular structure corresponding to the distance distribution measured at about 380 femtoseconds into the reaction (dashed line at bottom). (David Sanchez/Stanford University)

The new study used UED – a technique in which researchers send an electron beam with high energy, measured in millions of electronvolts (MeV), through a sample – to precisely measure distances between pairs of atoms.

Taking snapshots of these distances at different intervals after an initial laser flash and tracking how they change allows scientists to create a stop-motion movie of the light-induced structural changes in the sample.

The electron beam also produces strong signals for very dilute samples, such as the CHD gas used in the study, said SLAC scientist Xijie Wang, director of the MeV-UED instrument.

SLAC Megaelectronvolt Ultrasfast Electron Diffraction Instrument: MeV-UED

“This allowed us to follow the ring-opening reaction over much longer periods of time than before.”

Surprising details

The new data revealed several surprising details about the reaction.

They showed that the movements of the atoms accelerated as the CHD ring broke, helping the molecules rid themselves of excess energy and accelerating their transition to the stretched-out HT form.

The movie also captured how the two ends of the HT molecule jiggled around as the molecules became more and more linear. These rotational motions went on for at least a picosecond, or a trillionth of a second.

“I would have never thought these motions would last that long,” Wolf said. “It demonstrates that the reaction doesn’t end with the ring opening itself and that there is much more long-lasting motion in light-induced processes than previously thought.”

A method with potential

The scientists also used their experimental data to validate a newly developed computational approach for including the motions of atomic nuclei in simulations of chemical processes.

“UED provided us with data that have the high spatial resolution needed to test these methods,” said Stanford chemistry professor and PULSE researcher Todd Martinez, whose group led the computational analysis. “This paper is the most direct test of our methods, and our results are in excellent agreement with the experiment.”

In addition to advancing the predictive power of computer simulations, the results will help deepen our understanding of life’s fundamental chemical reactions, Wolf said: “We’re very hopeful our method will pave the way for studies of more complex molecules that are even closer to the ones used in life processes.”

Other research institutions involved in this study were the University of York, UK; University of Nebraska-Lincoln; University of Potsdam, Germany; University of Edinburgh, UK; and Brown University. Large parts of this work were financially supported by the DOE Office of Science. SLAC’s MeV-UED instrument is part of LCLS, a DOE Office of Science user facility.

See the full article here .

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

SLAC/LCLS

SLAC/LCLS II projected view

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.