IR – Lightsources.org

Watching complex molecules at work

2020/01/142020/01/15

A new method of infrared spectroscopy developed at BESSY II makes single-measurement observation and analysis of very fast as well as irreversible reaction mechanisms in molecules feasible for the first time.

Previously, thousands of such reactions have had to be run and measured for this purpose. The research team has now used the new device to investigate how rhodopsin molecules change after activation by light – a process that is the basis of how we see.

Time-resolved infrared spectroscopy in the sub-millisecond range is an important method for studying the relationship between function and structure in biological molecules. However, the method only works if the reaction can be repeated many thousands of times. This is not the case for a large number of biological processes, though, because they often are based on very rapid and irreversible reactions, for example in vision. Individual light quanta entering the rods of the retina activate the rhodopsin protein molecules, which then decay after fulfilling their phototransductionfunction.

Image: Rhodopsin before (left) and after activation by light (right): The activation causes changes in functional groups inside the molecule (magnifying glass), which affect the entire molecule.
Credit: E. Ritter/HZB

Analysis of fingermarks with synchrotron techniques provide new insights

2019/09/062019/09/06

A new study by researchers from Curtin University using the infrared (IR) and X-ray fluorescence microscopy (XFM) beamlines at the Australian Synchrotron has provided a better understanding of the chemical and elemental composition of latent fingermarks.

The findings by lead researchers Prof Simon Lewis and Dr Mark Hackett may provide opportunities to optimise current fingermark detection methods or identify new detection strategies for forensic purposes.
Latent fingermarks are generally described as those requiring some process to make them readily visible to the eye. These fingermarks are typically made up of natural skin secretions, along with contaminants (such as food or cosmetics) picked up from various surfaces.
The detection of latent fingermarks is often crucial in forensic investigations, but this is not always a straightforward task. “We know that there are issues in detecting fingermarks as they get older, and also under certain environmental conditions”, said Lewis, whose main research focus is forensic exchange evidence.

“In order to improve our ability to detect fingermarks, we need to understand the nature of fingermark residue, and this includes both the organic and inorganic components. Many chemical components in fingermark residue are present at very low levels, and we don’t know how they are distributed within the fingermark. This is what took us to the Australian Synchrotron.”

Urea susbstitutes noble metal catalysts

2019/02/222019/02/25

… for the photodegradation of organic polluants.

A new laser-based technique developed by the Institute of Materials Science (ICMAB-CSIC) uses urea, a common substance in the chemical industry and a low-cost alternative to noble metal co-catalyst, to enable a more efficient, one-step production of hybrid graphene-based organic-inorganic composite layers for environmental remediation, photodegradation of antibiotic contaminants from wastewater. The composition and chemical bonds of the urea-enriched thin layers were studied in detail using synchrotron light at the ALBA Synchrotron.
Human activity is increasing the amount of pollutants in water and air, as well as in all sorts of materials at home and work place. The existence of antibiotic contamination is undeniably one of the most threatening challenges to date, at a time when antibiotic-resistant bacteria has already been flagged as the next world-wide pandemic crisis.
Semiconductor photocatalysts have long been investigated for environmental remediation because they can degrade or mineralize a wide range of organic contaminants as well as pathogens. Research focuses on addressing some drawbacks that prevent their use on a large scale. On the one hand, many photocatalysts are activated only by UV radiation which represents solely a small fraction of the total available solar emission. On the other hand, the recombination of the photogenerated electron-hole pairs that enable the decomposition of the pollutant is usually faster than the oxidation reactions that cause the degradation of organic molecules. As a consequence, noble metal co-catalysts acting as electron scavengers, such as gold or platinum, are needed in the process.

>Read more on the ALBA website

Image: Researchers Ángel Pérez del Pino and Enikö György from the ICMAB-CSIC together with Ibraheem Yousef, scientists responsible of MIRAS beamline at ALBA.

Single atoms can make more efficient catalysts

2019/01/072019/01/31

Detailed observations of iridium atoms at work could help make catalysts that drive chemical reactions smaller, cheaper and more efficient.

Catalysts are chemical matchmakers: They bring other chemicals close together, increasing the chance that they’ll react with each other and produce something people want, like fuel or fertilizer.

Since some of the best catalyst materials are also quite expensive, like the platinum in a car’s catalytic converter, scientists have been looking for ways to shrink the amount they have to use.

Now scientists have their first direct, detailed look at how a single atom catalyzes a chemical reaction. The reaction is the same one that strips poisonous carbon monoxide out of car exhaust, and individual atoms of iridium did the job up to 25 times more efficiently than the iridium nanoparticles containing 50 to 100 atoms that are used today.

>Read more on the SSRL at SLAC website

Image: Scientists used a combination of four techniques, represented here by four incoming beams, to reveal in unprecedented detail how a single atom of iridium catalyzes a chemical reaction.
Credit: Greg Stewart/SLAC National Accelerator Laboratory

Insights into Titan’s atmosphere

2018/11/132018/11/22

Terahertz/Far Infrared beamlines assisted investigation into possible composition of lower atmosphere of Saturn’s moon Titan.

Although firmly located on earth, the Australian Synchrotron’s Terahertz/Far Infrared beamline (THz/Far IR) is one of three synchrotron facilities in the word able to simulate the extreme conditions of distant planetary worlds.
The most recently reported research using the beamline published in Earth and Space Chemistry, involved recreating the pressure and temperatures environments in the hazy atmosphere surrounding Saturn’s moon Titan.

“We are interested in Titan because it is the most Earth-like of the planetary bodies possessing an atmosphere of mostly nitrogen and methane,” said co-author Rebecca Auchettl (pictured above), a PhD candidate who was supervised by Dr Courtney Ennis, formerly of La Trobe University now at the University of Otago in New Zealand.

Image: Co-author Rebecca Auchettl, PhD candidate.

Expanding the infrared nanospectroscopy window

2018/10/262018/11/04

The ability to investigate heterogeneous materials at nanometer scales and far-infrared energies will benefit a wide range of fields, from condensed matter physics to biology.

Scientific studies require tools that match the natural length and energy scales of the phenomena under investigation. For many questions in biology, quantum materials, and electronics, this means nanometer spatial resolution combined with far-infrared energies. For example, scientists might want to study collective electron oscillations in quantum materials for optoelectronic circuits, or the characteristic vibration modes of protein molecules in biological systems.

A recently developed infrared technique—synchrotron infrared nanospectroscopy (SINS)—combines broadband synchrotron light with atomic-force microscopes to enable infrared imaging and spectroscopy at the nanoscale. However, the technique could only be used in a narrow range of the electromagnetic spectrum that excluded far-infrared wavelengths, due to a scarcity of suitable light sources and detectors for that range. In this work, researchers extended SINS to far-infrared wavelengths, opening up a whole new experimental regime.

Image: Left: Nanoscale images of SiO₂ hole array, obtained using atomic-force microscopy (AFM, top) and synchrotron infrared nanospectroscopy (SINS, bottom), demonstrating SINS contrast between patterned SiO₂ and underlying Si substrate with ~30 nm spatial resolution (inset). Scale bar = 200 nm. Right: SINS broadband spectroscopic data for SiO₂, taken along dotted line in images at left, showing amplitude (top) and phase (bottom) information from asymmetric Si–O stretching (1200 cm^–1) and bending (460 cm^–1) modes. The lower-energy bending mode had previously been inaccessible with this technique.

Infrared beams show cell types in a different light

2018/08/232018/08/30

Berkeley Lab scientists developing new system to identify cell differences.

By shining highly focused infrared light on living cells, scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) hope to unmask individual cell identities, and to diagnose whether the cells are diseased or healthy.
They will use their technique to produce detailed, color-based maps of individual cells and collections of cells – in microscopic and eventually nanoscale detail – that will be analyzed using machine-learning techniques to automatically sort out cell characteristics.

Using microscopic color maps to unlock cell identity

Their focus is on developing a rapid way to easily identify cell types, and features within cells, to aid in biological and medical research by providing a way to probe living cells in their native environment without harming the cells or requiring obtrusive cell-labeling techniques.
“This is totally noninvasive,” said Cynthia McMurray, a biochemist and senior scientist in Berkeley Lab’s Molecular Biophysics and Integrated Bioimaging (MBIB) Division who is leading this new imaging effort with Michael Martin, a physicist and senior staff scientist at Berkeley Lab’s Advanced Light Source (ALS).
The ALS has dozens of beamlines that produce beams of intensely focused light, from infrared to X-rays, for a broad range of experiments.

Image: From left to right: Aris Polyzos, Edward Barnard, and Lila Lovergne, pictured here at Berkeley Lab’s Advanced Light Source, are part of a research team that is developing a cell-identification technique based on infrared imaging and machine learning.
Credit: Marilyn Chung/Berkeley Lab

Synchrotron infrared beamline optics optimized…

2018/08/162018/10/23

…for nano-scale vibrational spectroscopy. First experimental report of a special optical layout dedicated to correct typical aberrations derived from large extraction ports in IR beamlines.

Infrared nanospectroscopy represents a major breakthrough in chemical analysis since it allows the identification of nanomaterials via their natural (label free) vibrational signatures. Classically powered by laser sources, the experiment called scattering Scanning Near-field Optical Microscopy (s-SNOM) has become a standard tool for investigations of chemical and optical properties of materials beyond the diffraction limit of light.

Lately, s-SNOM is achieving unprecedent sensitivity range by exploring the outstanding spectral irradiance of synchrotron light sources in the full range of infrared (IR) radiation. In the last few years, the combination of s-SNOM and ultra-broadband IR synchrotron (SINS or nano-FTIR) has helped studies in relevant scientific fronts involving atomic layered materials, fundamental optics, nanostructured bio-materials and, very recently, it was demonstrated to be feasible to work in the far-IR.

IR ports in synchrotron storage rings can be up to a thousand times more brilliant than classical IR black body sources. This advantage allowed IR beamlines to be the only places capable of performing IR micro-spectroscopy for many years. However, in comparison to X-ray ports, IR beamlines require large apertures for allowing long wavelengths to be extracted. Consequently, IR beamlines typically present optical aberrations such as extended source depth and coma.

Images (extracts): Figure 1 – Proposed optical layout, IR extraction chamber indicating the source depth, conical mirror illustration, aberration-corrected focal spot at the sample stage and nano-FTIR experimental scheme in operation in the IR endstation of the LNLS. Figure adapted from R. Freitas et al., Optics Express 26, 11238 (2018).

Pressure tuning of light-induced superconductivity in K3C60

2018/07/242018/09/03

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological application is hindered by their low operating temperature, which in the best case can reach -70 degrees Celsius. Researchers of the group of Prof. A. Cavalleri at the Max Planck Institute of the Structure and Dynamics of Matter (MPSD) in Hamburg have routinely used intense laser pulses to stimulate different classes of superconducting materials. Under specific conditions, they have detected evidences of superconductivity at unprecedented high temperatures, although this state persisted very shortly, just for a small fraction of a second.
An important example is that of K₃C₆₀, an organic molecular solidformed by weakly-interacting C60 “buckyball” molecules (60 carbon atoms bond in the shape of a football),which is superconducting at equilibrium below a critical temperature of -250 degrees Celsius. In 2016, Mitrano and coworkers at the MPSD discovered that tailored laserpulses, tuned to induce vibrations of the C60 molecules,can induce a short-lived, highly conducting state with properties identical to those of a superconductor, up to a temperature of at least -170 degrees Celsius, far higher than the equilibrium critical temperature (Mitrano et al., Nature, 530, 461–464 (2016)).

In their most recent investigation, A. Cantaluppi, M. Buzzi and colleagues at MPSD in Hamburg went a decisive step further by monitoring the evolution of the light-induced state in K₃C₆₀ once external pressure was applied by a diamond anvil cell (Figure 1). At equilibrium, when pressure is applied, the C₆₀ molecules in the potassium-doped fulleride are held closer to each other. This weakens the equilibrium superconducting state and significantly reduces the critical temperature. The steady state optical response of K₃C₆₀at different pressures and temperatures was determined via Fourier-transform infrared spectroscopy, by exploiting the high brightness of the synchrotron radiation available at the infrared beamline SISSI at Elettra.

>Read more on the Elettra website

Image: Light-induced superconductivity in K₃C₆₀ was investigated at high pressure in a Diamond Anvil Cell.
Credit: Jörg Harms / MPSD

An electrifying view on catalysis

2018/07/032018/07/12

The future of chemistry is ‘electrifying’: With increasing availability of cheap electrical energy from renewables, it will soon become possible to drive many chemical processes by electrical power. In this way, chemical products and fuels can be produced via sustainable routes, replacing current processes which are based on fossil fuels.

In most cases, such electrically driven reactions make use of so-called electrocatalysts, complex materials which are assembled from a large number of chemical componentAs. The electrocatalyst plays an essential role: It helps to run the chemical reaction while keeping the loss of energy minimal, thereby saving as much renewable energy as possible. In most cases, electrocatalysts are developed empirically and the chemical reactions at their interfaces are poorly understood. A better understanding of these processes is essential, however, for fast development of new electrocatalysts and for a directed improvement of their lifetime, one of the most important factors that currently limit their applicability.

>Read more on the Elettra website

Figure: Introducing well-defined model electrocatalysts into the field of electrochemistry.

Probing the complex dielectric properties of MOFs

2018/06/222018/07/18

Gaining fundamental insights into the full dielectric behaviour of MOFs across the infrared and THz.

An international team of researchers from Oxford, Diamond, and Turin, has demonstrated the novel use of synchrotron radiation infrared (SRIR) reflectivity experiments, to measure the complex and broadband dielectric properties of metal-organic framework (MOFs) materials. Open framework compounds like MOFs have the potential to revolutionise the field of low-k dielectrics, because of their tuneable porosity coupled with an enormous combination of physicochemical properties not found in conventional systems. Furthermore, next generation IR optical sensors and high-speed terahertz (THz) communication technologies will stand to benefit from an improved understanding of the fundamental structure-property relations underpinning novel THz dielectric materials.

Image: (extract) The high-resolution reflectivity data obtained were subsequently used to determine the real and imaginary components of the complex dielectric function by adopting the Kramers−Kronig Transformation theory.
Credit: ACS

From Moon Rocks to Space Dust

2018/06/112018/07/12

Specialized equipment, techniques, and expertise at Berkeley Lab attract samples from far, far away.

From moon rocks to meteorites, and from space dust to a dinosaur-destroying impact, the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has a well-storied expertise in exploring samples of extraterrestrial origin.

This research – which has helped us to understand the makeup and origins of objects within and beyond our solar system – stems from the Lab’s long-standing core capabilities and credentials in structural and chemical analyses and measurement at the microscale and nanoscale.

Berkeley Lab’s participation in a new study, detailed June 11 in the journal Proceedings of the National Academy of Sciences, focused on the chemical composition of tiny glassy grains of interplanetary particles – likely deposited in Earth’s upper atmosphere by comets – that contain dust leftover from the formative period of our solar system.

That study involved experiments at the Lab’s Molecular Foundry, a nanoscale research facility, and the Advanced Light Source (ALS), which supplies different types of light, from infrared light to X-rays, for dozens of simultaneous experiments.

Image: Moon dust and rock samples photographed at Berkeley Lab.
Credit: Berkeley Lab

SESAME light source brings second beamline into service

2018/05/012018/05/03

Allan, Jordan, 30 April 2018. At 11:21 pm local time (GMT +3) scientists at the SESAME light source brought the laboratory’s infrared (IR) spectromicroscopy beamline into service for the first time.

This beamline is a completely new beamline. It was designed and built in collaboration with the French Soleil Synchrotron. It is SESAME’s second operational beamline, and it joins an X-ray beamline that saw first light on 23 November 2017. The addition of the IR beamline will enable the application of infrared microspectroscopy and imaging in a wide range of fields, including surface and materials science (e.g. characterization of new nanomaterials for solar cell fabrication and for drug delivery mechanisms), biochemistry, archaeology, geology, cell biology, biomedical diagnostics and environmental science (e.g. air and water pollution)

“I’ve been waiting a long time for this moment,” said Gihan Kamel, SESAME’s IR beamline scientist. “It’s very satisfying to see light in the beamline, and to be able to start doing research here that we previously had to travel to Europe to carry out.”

In preparation for the SESAME research programme, a number of thematic schools are being held across the region in a collaboration involving SESAME and European partners including the European Union through its Open SESAME project. One of these was held at SESAME earlier this month, covering science on the IR beamline. Students came from across the region and learned techniques ranging from sample preparation to data analysis.

“The infrared beamline has a mouth-watering research programme lined up,” said SESAME Scientific Director Giorgio Paolucci, “and it is great to see so many young people from across the region preparing to embark on careers in science.”

>Read more on the SESAME website