Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

U of T team makes ’movie stars’ of atoms

21.11.2003


Chemists at the University of Toronto have captured atom-scale images of the melting process-revealing the first images of the transition of a solid into a liquid at the timescale of femtoseconds, or millionths of a billionth of a second.

The result is an unprecedented "movie" detailing the melting process as solid aluminum becomes a liquid. This new study, led by Professor R. J. Dwayne Miller of the Departments of Chemistry and Physics, received the prestigious cover position of the Nov. 21 issue of Science.

"Imagine being able to see atoms as they move in real time," says Miller, who holds the Canada Research Chair in Femtoscience. "Chemistry and biology are fundamentally governed by changes in atomic structure. We now have a tool that will let us observe the most fundamental processes at the atomic level of inspection with sufficient time resolution to allow us to see chemical and biological events as they happen."



Since no camera shutter can open and close at the femtosecond time scale, the team built a special system using a laser and an electron gun inside a vacuum chamber. The energy of the laser’s blast superheated small sections of the aluminum to over 1,000 degrees Celsius, exceeding the metal’s melting point of 660 degrees Celsius.

Releasing a 600-femtosecond electron pulse at virtually the same moment of the laser blast, they captured an image of the aluminum atoms. This revealed the melting process at 0.5-picoseconds (one thousandth of a billionth of a second) after the laser struck the aluminum. However, capturing the complete melting sequence required that they repeat the process several times, each time firing the electron pulse a few hundred femtoseconds later. This revealed the melting process at 1.5-, 2.5- and 3.5-picoseconds after the laser pulse.

The "movie" the group saw when they put the frames together revealed that the solid literally shook itself apart at the atomic level. Liquids are fundamentally different than solids in that the atomic positions are random in liquids but ordered in solids. The team was able to watch, step by step, as the initially well-ordered arrangement of aluminum atoms in the solid changed into the disordered state of the liquid. The aluminum melted in an astonishingly short time-within 3.5 picoseconds.

This work represents the first atomic level view of the melting process, one of the simplest structural changes of matter. The team stresses the scientific implications of being able to watch atoms rearrange themselves on the femtosecond timescale. "Chemists think of reactions in terms of atoms moving around as bonds are broken and formed," says Jason Dwyer, a graduate student in Miller’s laboratory and a co-author of the paper. "It is one of the dreams of chemistry to be able to actually watch that as it happens, and we now have a technique that lets us do that."


The research is funded by the Canada Foundation for Innovation, the Ontario Innovation Trust, the Natural Sciences Engineering Research Council of Canada and the U of T Connaught Fund.

CONTACT:

R.J. Dwayne Miller
Department of Chemistry
(currently in Germany)
011-49-30-897-48221 2-6pm EST
011-49-30-6392-1429 7am-12pm
dmiller@Lphys.chem.utoronto.ca

Brad Siwick
Department of Physics
416-978-0366
siwick@Lphys.chem.utoronto.ca

Jason Dwyer
Department of Chemistry
416-978-0366
jdwyer@Lphys.chem.utoronto.ca

Robert Jordan
Department of Chemistry
416-978-0366
robert@Lphys.chem.utoronto.ca

Nicolle Wahl
U of T Public Affairs
416-978-6974
nicolle.wahl@utoronto.ca

Nicolle Wahl | University of Toronto
Further information:
http://www.utoronto.ca/

More articles from Life Sciences:

nachricht Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel

nachricht Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>