HZB scientists have apply a new method – 'inverse Partial Fluorescence Yield' (iPFY) on micro-jet – which will enable them to probe the electronic structure of liquids free of sample damages. The experiments are performed in vacuum conditions at the LiXEdrom experimental chamber, where a fluid stream of micrometer diameter is moving freely through vacuum and is continuously irradiated with X-ray radiation.
Metal ions in solution can be examined using soft X-ray radiation. In addition to metal ions, the free fluid stream in the vacuum also contains oxygen, which, following X-ray irradiation, begins to glow, ultimately affecting metal ion
absorption. Researchers can now calculate the metal ions’ absorptive strength and make inferences regarding the ions' electronic structures. Fig: HZB
These kinds of experiments are important as they reveal the interaction strength of the X-rays with the liquids and therefore allow for the structural analysis of substances dissolved in solution. “The method will achieve its absolute apprehension when will be applied to metal ions that are part of chemical catalysts used for clean energy production and biocatalysts (protein enzymes) used in biochemical transformation inside the living cells – the team leader Prof. Aziz stated, which is the next milestone in our research progress. Previously, these types of experiments were so far only possible if the fluid was contained between two membranes, where radiation damages and membrane induced artifacts were a crucial issue.
HZB's Young Investigator Group for Functional Materials in Solution headed by Prof. Dr. Emad Aziz has already applied the new method in iron ions dissolved in aqueous solution. Their findings have now been published in the Journal of Physical Chemistry Letters (DOI: 10.1021/jz300403n).
The researchers used X-ray radiation – generated by HZB's own electron storage ring BESSY II – to examine iron ions in aqueous solution. "We measured the absorption strength of the X-rays from our Fe 2+ and oxygen ions in the liquid micro-beam" explains Malte Gotz, who performed the experiments as part of his graduate research. "From here, we were able to draw conclusions regarding the electronic structure of the iron ions and further more to investigate the interaction of iron ions with the water solvent, " says Gotz.
The researchers used a new approach to measuring X-ray absorption of liquids. "Oxygen, which, along with iron ions, is also present in the solution, turns out to play a rather important role. If X-ray light is used to irradiate – and thereby the oxygen that is present in the water will absorb this radiation, and will end up emitting light for a brief period of time. You might compare it to the glow-in-the-dark of a clock," Gotz explains. If you now reduce the amount of incoming radiation by having a different material – in this case ionic iron absorbs it, it will directly reduce the amount of radiation emitted by the oxygen. "This in turn allows us to measure the absorption strength of ionic iron," says Gotz.
According to Emad Aziz, by definition, any measurement obtained at the free fluid stream is highly accurate. "A major advantage of our protocol is the fact that besides measuring only the signal from our fluid stream – without having to account for any artifacts induced by the surrounding container – we are also measuring a continuously fresh liquid sample," Aziz explains. In their studies the scientists found that iron ions suspended in the solution interact strongly with the solvent; a conclusion drawn by the strong 'Coster Kroenig decay process’ observed in the liquid system, which were thus far observed only in solid iron. "We concluded that ions interact more strongly with water than was previously thought," says Aziz.
Our next step is to apply the new method to biological functional materials where the transition metals play key biological functions- such as oxygen-carrying iron in human blood. New and deep insights into these catalysts’ structure and function are the challenge of our scientific research.
Dr. Emad F. Aziz | EurekAlert!
World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Life Sciences
17.07.2018 | Information Technology
17.07.2018 | Power and Electrical Engineering