Aqueous iron interacts as strong as solid iron

Metal ions in solution can be examined using soft X-ray<br />radiation. In addition to metal ions, the free fluid stream<br />in the vacuum also contains oxygen, which, following X-ray<br />irradiation, begins to glow, ultimately affecting metal ion<br /> absorption. Researchers can now calculate the metal ions’<br /> absorptive strength and make inferences regarding the<br />ions' electronic structures.<br />
Fig: HZB

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

Advances spectroscopy research: HZB scientists come up with new method for examining the structure of metal ions-complexes in solution

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.

HS

  • Copy link

You might also be interested in

  • Review on ocular particle therapy (OPT) by international experts
    Science Highlight
    03.09.2024
    Review on ocular particle therapy (OPT) by international experts
    A team of leading experts in medical physics, physics and radiotherapy, including HZB physicist Prof. Andrea Denker and Charité medical physicist Dr Jens Heufelder, has published a review article on ocular particle therapy. The article appeared in the Red Journal, one of the most prestigious journals in the field. It outlines the special features of this form of eye therapy, explains the state of the art and current research priorities, provides recommendations for the delivery of radiotherapy and gives an outlook on future developments.
  • Small powerhouses for very special light
    Science Highlight
    27.06.2024
    Small powerhouses for very special light
    An international team presents the functional principle of a new source of synchrotron radiation in Nature Communications Physics. Steady-state microbunching (SSMB) allows to build efficient and powerful radiation sources for coherent UV radiation in the future. This is very attractive for applications in basic research as well in the semiconductor industry.
  • Sebastian Keckert wins Young Scientist Award for Accelerator Physics
    News
    21.03.2024
    Sebastian Keckert wins Young Scientist Award for Accelerator Physics
    Dr Sebastian Keckert has been awarded the Young Scientist Award for Accelerator Physics of the German Physical Society (DPG). The prize is endowed with 5000 euros and was presented to him on 21.03. during the spring conference in Berlin. It honours the physicist's outstanding achievements in the development of new superconducting thin-film material systems for cavities.