Elemental and chemical imaging analyses showed that sea salt particles react with water-soluble organic acids in the atmosphere through a unique mechanism which had been overlooked in atmospheric chemistry. The reactions release volatile hydrogen chloride into the atmosphere and leave behind sea salt particles drained of chloride.
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ALS Work Using Spectroscopy
These techniques are used to study the energies of particles that are emitted or absorbed by samples that are exposed to the light-source beam and are commonly used to determine the characteristics of chemical bonding and electron motion.
Two Electron Holes in Hematite Facilitate Water Splitting
Hematite is a promising electrode material for solar-powered water splitting—an important reqirement for producing hydrogen fuel with zero emissions. At Beamline 7.0.1, researchers have gained a better understanding of hematite’s electronic structure through soft x-ray spectroscopy performed in situ and “operando.” Read more »
Direct Kinetic Measurements of a Criegee Intermediate
“Criegee intermediates” are elusive molecules that play a pivotal role in atmospheric chemistry and are also byproducts of key combustion reactions. At the Chemical Dynamics Beamline, the reaction rates of one form of Criegee intermediate was directly measured for the first time, with some surprising results. Read more »
Superconducting Topological Insulators
ARPES studies show that it’s possible to introduce superconductivity into a topological insulator. The resulting novel properties, such as relativistic electrons and quantum memory, may in the future provide the basis for a whole new type of computer.
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ALS Reveals New State of Matter
ALS user groups from Princeton and Stanford have been making waves this past year with several high-profile papers and extensive news coverage of their work on a new state of matter embodied by so-called “topological insulators,” materials that conduct electricity only on their surfaces. Read more »
Molecular Measurements of the Deep-Sea Oil Plume in the Gulf of Mexico
To study the effects of oil spilled from the Deepwater Horizon blowout, researchers collected deep-water samples from across the Gulf of Mexico and analyzied their physical, chemical, and microbiological properties using a variety of techniques, including SR-FTIR. Read more »
Platinum Nanoclusters Out-Perform Single Crystals
Researchers have found that under high pressure—comparable to the pressures at which many industrial technologies operate—platinum surfaces can change their structure dramatically in response to the presence of high-coverage reactants. Read more »
Observation of a Macroscopically Quantum-Entangled Insulator
It has recently been proposed that insulators with large band gaps and strong spin-orbit coupling can host a new phase of quantum matter called a topological insulator that is characterized by entangled wavefunctions. The proposal has now been realized by an international collaboration led by researchers from Princeton University who studied the electronic structure of insulating alloys of bismuth and antimony by means of angle-resolved photoemission spectroscopy (ARPES) and spin-resolved ARPES. Read more »
Reaction-Driven Restructuring of Bimetallic Nanoparticle Catalysts
Researchers have used an ambient-pressure x-ray photoelectron spectroscopy (APXPS) apparatus to demonstrate that bimetallic nanoparticle catalysts can undergo profound structural and chemical changes in response to reactive environments at ambient pressures, thereby opening the way for engineering catalysts with enhanced activity and selectivity. Read more » 
Particles from Comet 81P/Wild 2 Viewed by ALS Microscopes
NASA’s $200-million, seven-year-long Stardust mission returned to Earth thousands of tiny particles snagged from the coma of comet 81P/Wild 2. Four ALS beamlines and the researchers using them were among the hundreds of scientists and dozens of experimental techniques in facilities around the world that contributed to the preliminary examination of the first samples.
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