Sounds like the easiest thing in the world: a drop of water falls on a stone, where it comes into contact with oxide surfaces, which are found everywhere in nature. However, what is happening on an atomic scale in many respects remains unknown - although this knowledge could be significant for environmental chemistry.
In recent years, Professor Ulrike Diebold from the Institute of Applied Physics at TU Wien has developed new methods of investigation, which she now wants to use to get to the bottom of questions of this nature. She has now received an ERC Advanced Grant to do just this - one of the most lucrative and prestigious research awards in Europe. What is particularly remarkable is that this is the second ERC Advanced Grant Ulrike Diebold has been awarded; she received the first one in 2012. It is the 30th ERC grant for TU Wien in total.
Extremely important - but difficult to investigate
"What goes on at the interface between water and oxides is hugely significant for countless phenomena," says Ulrike Diebold. "Materials weather, land is shaped and formed and CO2 is removed from the atmosphere. In groundwater, oxide surfaces absorb noxious substances. Clouds emerge when water freezes onto mineral dust - the interaction of water and oxide surfaces is taking place everywhere around it." New technologies, such as the production of artificial fuels and other valuable chemicals, should also become possible when we have a better understanding of these atomic processes.
"There is huge interest in this phenomenon - and just one reason why there has been no research on it up to now: it is extremely difficult," explains Ulrike Diebold. The precise measurement of chemical and physical processes on an atomic scale needs to be done under very strictly controlled conditions. Experiments like these are normally conducted in an ultra-high vacuum. Otherwise, atoms and molecules from the air would distort the results and make it impossible to understand the processes occurring on the oxide surface.
However, water is unfortunately not compatible with an ultra-high vacuum: "At very low pressure, there is barely any liquid water - at least not for very long. It would evaporate very quickly," explains Ulrike Diebold. "Many of the usual methods that can otherwise be put to good use in surface physics simply cannot be used in our research."
The world's cleanest drops of water
Nevertheless, Diebold and her team have managed to solve the problem by using a special trick: a pointed metal "cooling finger" is introduced into the vacuum chamber. Ultrapure water vapour flows in and freezes around the cooling finger at around -140° C. The tip of the metal then heats up until an ultrapure drop of water forms that can then be used to take measurements.
Ulrike Diebold's team has also pulled off a number of important successes in the field of high-performance microscopy. Extremely good resolutions have been achieved by using specific vibration dampening. This makes it possible to take pictures or even videos of the movement of individual atoms. "It is only through these high-resolution images on an atomic scale that we can really understand which physical and chemical processes are occurring here," said Ulrike Diebold. "We are constantly being surprised and excited by our findings - and that will certainly continue in the new ERC project."
Ulrike Diebold studied at TU Wien, where she was also awarded her doctorate in 1990. She then moved to the USA, first taking up a post-doc research post at Rutgers University (New Jersey). She then pursued her career at Tulane University (New Orleans, Louisiana), where she worked as a professor until 2009. In 2010, she returned to TU Wien as Professor for Surface Physics at the Institute of Applied Physics.
Ulrike Diebold has already received a number of awards during the course of her career, including the Wittgenstein Award (in 2013) - the highest award for scientific excellence in Austria. Other awards she has received include the Arthur W. Adamson Award from the American Chemical Society, the Blaise Pascal Medal from the European Academy of Sciences and the City of Vienna's Science Prize (2019). Diebold holds an honorary doctorate awarded by the Brno University of Technology, she is a Fellow of the American Physical Society and other distinguished scientific associations in the USA, she is a member of the German National Academy of Sciences Leopoldina, the European Academy of Sciences, the Academia Europeae and the Austrian Academy of Sciences.
Prof. Ulrike Diebold
Institute of Applied Physics
Wiedner Hauptstraße 8–10, 1040 Vienna
Phone: +43 1 58801 13425
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