In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Illustration of driving chemical reactions in molecules with laser pulses (Graphic: MPQ, Laboratory of Attosecond Physics)
Like an accomplished chef, chemists have become very skilled at the manipulation of these parameters to produce many of the products that make our lives better.
But there are some things that resist these methods. As a result, researchers are continually looking for new techniques to apply. In particular, laser-based chemistry has been a goal for researchers since the invention of the laser in the 1960s. Applying a laser pulse of the correct color and duration to a molecule could, in principle, inject just the right amount of energy to modify a specific chemical bond and change the molecule into a more desirable configuration. In this sense, the laser can be thought of as a new type of reagent that drives a chemical reaction.
In practice, even a single molecule is a complicated system and finding the correct laser pulse characteristics to influence molecules is difficult. In addition, sophisticated laser pulse shaping devices can produce a nearly infinite number of pulse shapes, making a systematic search for the correct laser-molecule solution daunting.
A proven method for approaching this problem is to use experimental feedback to guide an adaptive search of the possible laser pulses. As in natural selection, laser pulses that provide a better outcome are given an increased chance to survive and have their characteristics contribute to the tailored pulse that ultimately produces the desired outcome. Such a method, however, is only as good as the feedback that drives it.
In an article published this week in the journal Nature Communications, researchers from Augustana College (SD) and Kansas State University (KSU) in the United States and from the Max Planck Institute for Quantum Optics (MPQ) and the Ludwig Maximilian University (LMU) in Munich, Germany, have reported an improved feedback technique. By imaging the dissociating molecule in three dimensions, a laser pulse can be optimized to drive the molecule to a very specific final state. This image-based technique can complement feedback methods that depend on optical spectroscopy. Furthermore, the researchers were able to use the dissociation images to guide theoretical work that revealed how the laser pulse was able to control the molecule, in this case driving acetylene ions from the normal HCCH configuration to the unusual HHCC configuration.
Building on the initial work done at MPQ, Augustana students developed a method for converting the image into feedback quickly enough to be useful in the experiment. They then developed a system of computer control linking the entire experiment as well as refining image-analysis techniques to evaluate the experimental data. Once this was accomplished, the experiment was conducted at the J.R. Macdonald Laboratory. Initial results stimulated the theoretical work performed at LMU to clarify the control mechanism.
“The experiment shows that improved feedback, provided by multi-dimensional imaging, enhances both our abilities to control chemical reactions and the physical insight that can be gained”, said Matthias Kling, research group leader at MPQ and assistant professor at KSU at the time the studies were conducted. “The new methodology provides new possibilities for the control of more complex systems including larger molecules, clusters, and nanoparticles. Multi-dimensional data provide stricter limitations for theory and will help to improve our models”, explains Regina de Vivie-Riedle, professor at LMU and leader of the group that performed the theory.
Augustana College personnel and equipment were funded by National Science Foundation Grant No. 0969687 and National Science Foundation/EPSCoR Grant No. 0903804. KSU operations and personnel were supported by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy. Additional funding was provided by support by the German Research Foundation via the Cluster of Excellence: “Munich Center for Advanced Photonics (MAP)” and via the DFG grants Kl-1439/2 and Kl-1439/3.Original publication:
Nature Communications 4:2895 DOI: 10.1038/ncomms3895 (2013).Contact:
Dr. Olivia Meyer-Streng | Max-Planck-Institut
DGIST develops 20 times faster biosensor
24.04.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)
New quantum liquid crystals may play role in future of computers
21.04.2017 | California Institute of Technology
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...
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...
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...
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...
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...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
24.04.2017 | Physics and Astronomy
24.04.2017 | Materials Sciences
24.04.2017 | Life Sciences