Competing quantum interactions enable single molecules to stand up
Nanoscale machinery has many uses, including drug delivery, single-atom transistor technology, or memory storage. However, the machinery must be assembled at the nanoscale which is a considerable challenge for researchers.
For nanotechnology engineers the ultimate goal is to be able to assemble functional machinery part-by-part at the nanoscale. In the macroscopic world, we can simply grab items to assemble them. It is not impossible to “grab” single molecules anymore, but their quantum nature makes their response to manipulation unpredictable, limiting the ability to assemble molecules one by one. This prospect is now a step closer to reality thanks to an international effort led by the Research Centre Jülich of the Helmholtz society in Germany including researchers from the Department of Chemistry at the University of Warwick.
In the paper, ‘The stabilization potential of a standing molecule’, published on the 10th November 2021 in the journal Science Advances, an international team of researchers have been able to reveal the generic stabilisation mechanism of a single standing molecule, which can be used in the rational design and construction of three-dimensional molecular devices at surfaces.
The scanning probe microscope (SPM) has brought the vision of molecular-scale fabrication closer to reality, because it offers the capability to rearrange atoms and molecules on surfaces, thereby allowing the creation of metastable structures that do not form spontaneously. Using SPM, Dr Christian Wagner and his team were able to interact with a single standing molecule, perylene-tetracarboxylic dianhydride (PTCDA) on a surface to study the thermal stability and temperature at which the molecule would cease to be stable and would drop back into its natural state where it adsorbs flat on the surface. This temperature stands at -259.15 Celsius, only 14 degrees above the absolute zero-temperature point.
Quantum chemical calculations performed in collaboration with Dr. Reinhard Maurer from the Department of Chemistry at the University of Warwick were able to reveal that the subtle stability of the molecule stems from the competition of two strong counteracting quantum forces, namely the long-range attraction from the surface and the short-range restoring force arising from the anchor point between molecule and the surface.
Dr Reinhard Maurer, from the Department of Chemistry at the University of Warwick comments:
“The balance of interactions that keeps the molecule from falling over is very subtle and a true challenge for our quantum chemical simulation methods. In addition to teaching us about the fundamental mechanisms that stabilise such unusual nanostructures, the project also helped us to assess and improve the capabilities of our methods.”
Dr Christian Wagner from the Peter Grünberg Institute for Quantum Nanoscience (PGI-3) at Research Centre Jülich comments:
“To make technological use of the fascinating quantum properties of individual molecules, we need to find the right balance: They must be immobilized on a surface, but without fixing them too strongly, otherwise they would lose these properties. Standing molecules are ideal in that respect. To measure how stable they actually are, we had to stand them up over and over again with a sharp metal needle and time how long they survived at different temperatures.”
Now that the interactions that give rise to a stable standing molecule are known, future research can work towards designing better molecules and molecule-surface links to tune those quantum interactions. This can help to increase stability and the temperature at which molecules can be switched into standing arrays towards workable conditions. This raises the prospect of nanofabrication of machinery at the nanoscale.
You can also read Jülich’s press release here:
Journal: Science Advances
DOI: 10.1126/sciadv.abj9751
Method of Research: Experimental study
Subject of Research: Not applicable
Article Title: The stabilization potential of a standing molecule
Article Publication Date: 10-Nov-2021
COI Statement: The authors declare that they have no competing interests.
Media Contact
Alice Scott
University of Warwick
alice.j.scott@warwick.ac.uk
Office: 0247-657-4255
All latest news from the category: Information Technology
Here you can find a summary of innovations in the fields of information and data processing and up-to-date developments on IT equipment and hardware.
This area covers topics such as IT services, IT architectures, IT management and telecommunications.
Newest articles
Planets form through domino effect
New radio astronomy observations of a planetary system in the process of forming show that once the first planets form close to the central star, these planets can help shepherd…
M87’s powerful jet unleashes rare gamma-ray outburst
Also known as Virgo A or NGC 4486, M87 is the brightest object in the Virgo cluster of galaxies, the largest gravitationally bound type of structure in the universe. It…
Accelerating 5G & 6G Applications
Fraunhofer HHI and Partners Launch First Open-Source 5G FR2 MIMO Demonstrator. Fraunhofer Heinrich-Hertz-Institut (HHI) and its partners, Allbesmart, National Instruments (NI), and TMYTEK, have unveiled the world’s first open-source 5G…