From The Kiel University [Christian-Albrechts-Universität zu Kiel] (DE): “Sharper than ever”

From The Kiel University [Christian-Albrechts-Universität zu Kiel] (DE)

9.20.22
Prof. Dr. Richard Berndt
Surface Physics
Institute of Experimental and Applied Physics
+49 431 880-3946
berndt@physik.uni-kiel.de

Physicists from Kiel make molecular vibrations more detectable.

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Dr. Alexander Weismann (left) and Dr. Jan Homberg investigate vibrating molecules in a scanning tunnelling microscope at Kiel University, which allows particularly precise experiments. © Julia Siekmann, Uni Kiel.

In molecules, the atoms vibrate with characteristic patterns and frequencies. Vibrations are therefore an important tool for studying molecules and molecular processes such as chemical reactions. Although scanning tunnelling microscopes can be used to image individual molecules, their vibrations have so far been difficult to detect. Physicists at Kiel University (CAU) have now invented a method with which the vibration signals can be amplified by up to a factor of 50. Furthermore, they increased the frequency resolution by far. The new method will improve the understanding of interactions in molecular systems and to further develop simulation methods. The research team has now published the results in the journal Physical Review Letters [below].

The discovery by Dr. Jan Homberg, Dr. Alexander Weismann and Prof. Dr. Richard Berndt from the Institute of Experimental and Applied Physics, relies on a special quantum mechanical effect, the so-called inelastic tunnelling. Electrons that pass through a molecule on their way from a metal tip to the substrate surface in the scanning tunnelling microscope can release energy to the molecule or take it up from it. This energy exchange occurs in portions determined by the properties of the respective molecule.

Normally, this energy transfer happens only rarely and is therefore difficult to measure. In order to amplify the measurement signal and simultaneously achieve a high frequency resolution, the team of the CAU used a special property of molecules on superconductors they had previously discovered: suitably arranged, the molecules show a state in the spectra that appears needle-shaped, very high and extremely sharp — the so-called Yu-Shiba-Rusinov resonance. The experiments were supported by theoretical work of Troels Markussen from the software company Synopsis in Copenhagen.

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In this microscope image the lead phthalocyanine molecules on a superconducting lead surface appear as four-leaf clovers. The vibrations of these molecules were studied with the new method. © Jan Homberg.

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The model shows the molecular arrangement on a lead substrate. © Jan Homberg

Science paper:
Physical Review Letters
See further images in the science paper.

See the full article here .

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The Kiel University [ Christian-Albrechts-Universität zu Kiel ] (DE) was founded back in 1665. It is Schleswig-Holstein’s oldest, largest and best-known university, with over 26,000 students and around 3,000 members of staff. It is also the only fully-fledged university in the state. Seven Nobel prize winners have worked here. The CAU has been successfully taking part in the Excellence Initiative since 2006. The Cluster of Excellence The Future Ocean, which was established in cooperation with the GEOMAR [Helmholtz-Zentrum für Ozeanforschung Kiel](DE) in 2006, is internationally recognized. The second Cluster of Excellence “Inflammation at Interfaces” deals with chronic inflammatory diseases. The Kiel Institute for the World Economy is also affiliated with Kiel University. The university has a great reputation for its focus on public international law. The oldest public international law institution in Germany and Europe – the Walther Schuecking Institute for International Law – is based in Kiel.

History

The University of Kiel was founded under the name Christiana Albertina on 5 October 1665 by Christian Albert, Duke of Holstein-Gottorp. The citizens of the city of Kiel were initially quite sceptical about the upcoming influx of students, thinking that these could be “quite a pest with their gluttony, heavy drinking and their questionable character” (German: mit Fressen, Sauffen und allerley leichtfertigem Wesen sehr ärgerlich seyn). But those in the city who envisioned economic advantages of a university in the city won, and Kiel thus became the northernmost university in the German Holy Roman Empire.

After 1773, when Kiel had come under Danish rule, the university began to thrive, and when Kiel became part of Prussia in the year 1867, the university grew rapidly in size. The university opened one of the first botanical gardens in Germany (now the Alter Botanischer Garten Kiel), and Martin Gropius designed many of the new buildings needed to teach the growing number of students.

The Christiana Albertina was one of the first German universities to obey the Gleichschaltung in 1933 and agreed to remove many professors and students from the school, for instance Ferdinand Tönnies or Felix Jacoby. During World War II, the University of Kiel suffered heavy damage, therefore it was later rebuilt at a different location with only a few of the older buildings housing the medical school.

In 2019, it was announced it has banned full-face coverings in classrooms, citing the need for open communication that includes facial expressions and gestures.

Faculties

Faculty of Theology
Faculty of Law
Faculty of Business, Economics and Social Sciences
Faculty of Medicine
Faculty of Arts and Humanities
Faculty of Mathematics and Natural Sciences
Faculty of Agricultural Science and Nutrition
Faculty of Engineering