22-Sep-2022 - Christian-Albrechts-Universität zu Kiel (CAU)

Sharper than ever: Physicists make molecular vibrations more detectable

The new method will improve the understanding of interactions in molecular systems and to further develop simulation methods

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.

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.

Facts, background information, dossiers
More about Christian-Albrechts-Universität zu Kiel
  • News

    Exploding and weeping ceramics

    From coffee cups to bathroom tiles, ceramics are brittle.  Subject to the slightest deformation, they shatter. On the other end of the spectrum of materials, some of the most deformable materials known - that also support large stresses while they deform - are shape memory alloys.  The orig ... more

    Airy material with explosive power

    Theoretically, it only takes 450 grams of this material to lift an elephant: "Aerographene" owes this ability to its unique structure at the nano level. Visually similar to a black foam, it actually consists of a finely-structured tubular network based on graphene with numerous cavities. Th ... more

    Random effects make it difficult to optimise antibiotic therapy

    Antibiotic-resistant pathogens have become one of the greatest threats to public health. In just a few years, previously harmless bacterial infections may no longer be treatable and may once again become a leading non-natural cause of death, as they were before the antibiotic era began unti ... more