Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Thermal Radiation from Tiny Particles

22.06.2018

Researchers from Greifswald and Heidelberg have succeeded in performing time-resolved measurements of the internal energy distribution of stored clusters. The clusters investigated consisted of four cobalt atoms and an additional electron. Christian Breitenfeldt, a physicist at the University of Greifswald, presents, with his colleagues from the Max Planck Institute for Nuclear Physics in Heidelberg, the direct observation of the radiative heat exchange of these nanoparticles with their environment in the journal Physical Review Letters.

You do not have to touch a hot stove to feel its heat. If it is hot enough, you can see it glow. But, even at lower temperature it still emits light – although not visible to the human eye, but in the form of infrared rays.


Schematic of delayed electron emission after photoexcitation of a negatively charged four-atom cobalt cluster.

Drawing: Lutz Schweikhard

We have known the radiation laws for the objects of daily life as well as for celestial bodies like our sun since the studies of Max Planck, for which he received the Nobel Prize for physics of 1918. Isolated atoms also emit electromagnetic waves, according to very different, but also well-known laws. However, the details of radiative cooling of clusters – nanoparticles made of just a few atoms or molecules – have still not been clarified completely.

This topic is being approached by researchers at the Max Planck Institute for Nuclear Physics in Heidelberg, (MPIK) in collaboration with the University of Greifswald. As part of his doctoral work, Christian Breitenfeldt, a member of the research group led by Prof. Lutz Schweikhard in Greifswald, used the electrostatic ion-beam trap CTF (Cryogenic Trap for Fast Ion Beams) at MPIK’s scientific division led by Prof. Klaus Blaum, under the supervision of Prof. Andreas Wolf and Dr. Sebastian George.

The studies were performed with nanoparticles made of four cobalt atoms. These cobalt clusters were produced as negatively charged ions, i.e. with an additional electron, and captured in the CTF. Essentially, the trap consists of a pair of ion optical mirrors between which the stored ions bounce in an ultrahigh vacuum – which is very similar to a device that was developed in Greifswald and used extensively for precision mass measurements of exotic atomic nuclei at CERN.

If a nanoparticle has some thermal energy, i.e. ‘internal energy’ stored in the vibration of its atoms, the energy can be transferred to the electron. This can lead to the emission of the electron – sooner or later, depending on the amount of internal energy. As the cluster is no longer electrically charged, it is also stored no longer. After leaving the trap, it can be traced by a detector.

The aim of the experiments was to monitor the electron detachment in a time-resolved manner and to reconstruct the temporal development of the thermal distribution of the clusters’ internal energy. To this end, the clusters were irradiated with laser light of various wavelengths, i.e. at different photon energies. The electron emission, as a function of laser wavelength, served as a probe for the energy distribution of the stored cobalt clusters.

The internal energy distribution was probed 20 times per second over periods of six seconds, i.e. each series consisted of 120 measurements. This allowed the researchers to monitor the temporal development of the clusters’ thermal energy. It led to the reconstruction of the energy exchange by thermal radiation between the clusters and their environment, in this case the vacuum vessel, which was at room temperature.

If the clusters had a high level of internal energy at the beginning of the storage time, cooling was observed. In contrast, when the clusters came from a particularly cold cluster ion source, which was contributed to these measurements by a research group from the University of Kaiserslautern, the clusters were observed to warm up over time. In both cases, the clusters tried to gain an equilibrium in the flow of thermal radiation, i.e. to reach the environmental temperature of the experimental setup.

Both cooling and heating by thermal radiation are important aspects with respect to the stability of nanoparticles in free space. Under space conditions – in the ‘interstellar’ medium between the stars – the environmental temperature can be very low.

Thus, having gained these first results, follow-up experiments are currently being performed where these processes are being investigated at much lower temperatures, just a few degrees above absolute zero. To achieve this, the cryogenic storage ring CSR is being applied, which started work recently at the Max-Planck-Institute of Nuclear Physics.

The experiments currently being performed – again using negative four-atomic cobalt clusters – have already shown that the energy exchange via thermal radiation slows down significantly at very low temperatures. The long storage duration of ions in the CSR (up to hours) are proving to be of particular advantage for the investigation of molecules and clusters under interstellar conditions.

The results on the radiative cooling and heating of small cobalt clusters were published in the journal Physical Review Letters 120, 253001 – Published 21 June 2018
Long-term monitoring of the internal energy distribution of isolated cluster systems
C. Breitenfeldt, K. Blaum, S. George, J. Göck, G. Guzmán-Ramírez, J. Karthein, T. Kolling, M. Lange, S. Menk, C. Meyer, J. Mohrbach, G. Niedner-Schatteburg, D. Schwalm, L. Schweikhard, A. Wolf
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.253001
DOI: https://doi.org/10.1103/PhysRevLett.120.253001
Extended press release in German: https://physik.uni-greifswald.de/ag-schweikhard/further-links/press-releases/

Contacts
Dr. Sebastian George
Institute of Physics, University of Greifswald
Research Group ‘Atomic and Molecular Physics’
Felix-Hausdorff-Straße 6, 17489 Greifswald
Tel.: +49 3834 420 4700
sebastian.george@uni-greifswald.de
https://physik.uni-greifswald.de/ag-schweikhard/group-members/george/

Prof. Dr. Lutz Schweikhard
Institute of Physics, University of Greifswald
Research Group ‘Atomic and Molecular Physics’
Felix-Hausdorff-Straße 6, 17489 Greifswald
Tel.: +49 3834 420 4700
lschweik@physik.uni-greifswald.de
https://physik.uni-greifswald.de/ag-schweikhard/
http://www.researchgate.net/profile/Lutz_Schweikhard

Prof. Dr. Andreas Wolf
Max-Planck-Institute for Nuclear Physics
Department ‘Stored and Cooled Ions’
Saupfercheckweg 1, 69117 Heidelberg
Tel.: +49 6221 516 851
andreas.wolf@mpi-hd.mpg.de
https://www.mpi-hd.mpg.de/blaum/members/molecular-qd/wolf.de.html

Prof. Dr. Gereon Niedner-Schatteburg
Institute of Physical and Theoretical Chemistry,
University of Kaiserslautern
Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern
Tel.: +49 631 205 2536
gns@chemie.uni-kl.de
https://www.chemie.uni-kl.de/gns/

Jan Meßerschmidt | idw - Informationsdienst Wissenschaft

More articles from Physics and Astronomy:

nachricht (Re)solving the jet/cocoon riddle of a gravitational wave event
22.02.2019 | Max-Planck-Institut für Radioastronomie

nachricht Exotic spiraling electrons discovered by physicists
19.02.2019 | Rutgers University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: (Re)solving the jet/cocoon riddle of a gravitational wave event

An international research team including astronomers from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has combined radio telescopes from five continents to prove the existence of a narrow stream of material, a so-called jet, emerging from the only gravitational wave event involving two neutron stars observed so far. With its high sensitivity and excellent performance, the 100-m radio telescope in Effelsberg played an important role in the observations.

In August 2017, two neutron stars were observed colliding, producing gravitational waves that were detected by the American LIGO and European Virgo detectors....

Im Focus: Light from a roll – hybrid OLED creates innovative and functional luminous surfaces

Up to now, OLEDs have been used exclusively as a novel lighting technology for use in luminaires and lamps. However, flexible organic technology can offer much more: as an active lighting surface, it can be combined with a wide variety of materials, not just to modify but to revolutionize the functionality and design of countless existing products. To exemplify this, the Fraunhofer FEP together with the company EMDE development of light GmbH will be presenting hybrid flexible OLEDs integrated into textile designs within the EU-funded project PI-SCALE for the first time at LOPEC (March 19-21, 2019 in Munich, Germany) as examples of some of the many possible applications.

The Fraunhofer FEP, a provider of research and development services in the field of organic electronics, has long been involved in the development of...

Im Focus: Regensburg physicists watch electron transfer in a single molecule

For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.

The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...

Im Focus: University of Konstanz gains new insights into the recent development of the human immune system

Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens

Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...

Im Focus: Transformation through Light

Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light

When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Global Legal Hackathon at HAW Hamburg

11.02.2019 | Event News

The world of quantum chemistry meets in Heidelberg

30.01.2019 | Event News

Our digital society in 2040

16.01.2019 | Event News

 
Latest News

How the intestinal fungus Candida albicans shapes our immune system

22.02.2019 | Life Sciences

Correct antibiotic dosing could preserve lung microbial diversity in cystic fibrosis

22.02.2019 | Health and Medicine

The evolution of grain yield – Decoding the genetic basis of floret fertility in wheat

22.02.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>