Physicists from Jülich, Marburg, Regensburg and Graz win ERC Synergy Grant for ultra-high spatial and temporal resolution imaging of electron orbitals
Jülich, 25 October 2022 - Observing incredibly fast quantum processes and chemical reactions at the highest resolution: That is the goal of the "Orbital Cinema" project, for which physicists from the coordinating Forschungszentrum Jülich and the universities in Marburg, Regensburg and Graz today received one of the coveted Synergy Grants from the European Research Council (ERC). The researchers want for the first time to record the rapid movements of electrons in molecules in ultra-fast slow motion. This will provide a revolutionary insight into the inner structure of quantum leaps and charge transfer processes and show how chemical reactions can be controlled by electric fields and light.
Electrons are fascinating particles. According to the strange laws of quantum mechanics, they have no exact location. Instead, they buzz around with a certain probability in areas of space also known as orbitals. The shape of these orbitals is reminiscent of balloons or soap bubbles that surround the atomic nuclei. The great scientific interest in these structures is due to the fact that orbitals are considered the key to a better understanding of chemical reactions and quantum processes, for example in quantum computers or solar cells.
The European Research Council ERC has now awarded the physicists Prof. Stefan Tautz from Forschungszentrum Jülich, Prof. Ulrich Höfer from Philipps-Universität Marburg, Prof. Rupert Huber from the University of Regensburg and Prof. Peter Puschnig from the University of Graz one of the highest European awards for further research into these orbitals, a Synergy Grant worth 11.3 million euros. The prize can only be won as a team; with this category, the ERC supports scientifically groundbreaking endeavours by outstanding researchers that cannot be addressed by a single research group alone.
The four physicists from Germany and Austria are aiming to track orbitals not only in still images, but in a kind of "orbital cinematography". The bar could hardly be higher: electron orbitals are extremely tiny; at the same time, they move on incredibly short time scales. To accomplish this "Mission Impossible", the physicists are planning a completely new kind of super slow-motion microscope.
"We want to see, just like in slow motion, how orbitals change when chemical bonds form or break," explains Stefan Tautz from Forschungszentrum Jülich, who is coordinating the project. "In the natural and life sciences, people have long dreamed of being able to precisely measure these orbitals. The challenge lies in the fact that, as quantum mechanical quantities, they cannot actually be observed directly," says Stefan Tautz.
This will now become possible thanks to the synergy within the team. A few years ago, Peter Puschnig and Stefan Tautz, along with their colleague Mike Ramsey from Graz, demonstrated a spectacular imaging method - so-called photoemission orbital tomography - with which an electron orbital can be imaged as comprehensively as quantum mechanics allows.
The Jülich and Graz researchers succeeded in taking another important step in 2021 together with Ulrich Höfer's research group at the University of Marburg. Using a novel impulse microscope and a special laser, they were able to take snapshots of orbitals at an extremely high temporal resolution - though not yet a full film - as part of the DFG-funded Special Research Project SFB 1083.
Rupert Huber's research group, in turn, specialises in tracking processes that are faster than a single light oscillation period. Together with Ulrich Höfer, the group showed in 2018 that cinematic recordings in the required temporal resolution are possible in principle. The researchers had directly visualised how light fields accelerate electrons through solid matter.
"The combination of our expertise in the ERC Synergy project now creates something radically new," says a delighted Stefan Tautz, "namely a quantum laboratory in which one can directly observe how light fields dynamically shape orbitals."
The physicists hope to find answers to a whole range of fundamental questions. "The technique is expected to revolutionise the study of fundamental processes and phenomena in molecules that depend on the ultrafast dynamics of electrons and that are associated with a wide range of applications. This ranges from chemical and biochemical reactions to photovoltaics, photochemistry and next-generation optoelectronics to novel electronic components of the future with optical clock rates," explains theorist Peter Puschnig from the University of Graz.
The new Regensburg Centre for Ultrafast Nanoscopy (RUN) and the planned Jülich Helmholtz Quantum Center (HQC) play an important role here. "In 'Orbital Cinema' we are aiming for attosecond time resolution. An attosecond is 10-18 seconds, i.e. the billionth part of a billionth of a second; the attosecond relates to the second like a second to twice the age of the universe. Even processes that were previously considered instantaneous, such as electronic quantum leaps between orbitals, should reveal their internal structure on the attosecond scale," explains Ulrich Höfer, who will set up the new attosecond experiment together with Rupert Huber at the Regensburg Center for Ultrafast Nanoscopy (RUN).
"What we have set out to do is a totally new type of expedition into the nanocosmos. There are a number of known hypotheses about orbital dynamics that are relevant for future quantum technologies. We will definitely test these," says Rupert Huber, who was awarded the prestigious Gottfried Wilhelm Leibniz Prize in 2019 for his research. "But we also expect the unexpected. After all, our motion pictures will show the world on length and time scales that no human has ever seen before."
