Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Watching chemistry in motion: Chemical environments mapped using molecular vibrations

06.08.2014

Scientists have long known that a molecule's behavior depends on its environment. Taking advantage of this phenomenon, a group of researchers at the University of Chicago developed a new technique to map microscopic environments using the vibrations of molecules.

"It's a special new advance that will be broadly useful in studies of molecular and materials phenomena," said Andrei Tokmakoff, the Henry G. Gale Distinguished Service Professor in Chemistry at UChicago. He and two of his associates report their new technique in a paper published online in the journal Optics Express.


University of Chicago Postdoctoral fellows Carlos Baiz and Denise Schach worked with chemistry Professor Andrei Tokmakoff (not pictured), to develop ultrafast two-dimensional infrared microscopy.

Credit: Robert Kozloff/University of Chicago

The new technique builds on ultrafast two-dimensional infrared spectroscopy, which emerged approximately 15 years ago as a method to probe molecular vibrations. When a laser pulse strikes a molecule, parts of its energy is transferred into the vibrations of the molecule.

The ability of each single molecule to get rid of this excess energy, or relax, depends on the neighbors' ability to accept such energy. Thus molecules in different environments will relax at different rates, which are then used to determine the environment of individual molecules. Combining two-dimensional spectroscopy with a microscope enabled the researchers to directly visualize the microscopic variations in chemical environments.

"It's a new, hybrid technique that combines the spatial resolution of microscopy with the molecular information of infrared spectroscopy," said Carlos R. Baiz, a postdoctoral fellow and the article's lead author. The technique offers data on vibrational dynamics that traditional microscopy lacks, while adding spatial information that infrared spectroscopy alone can't provide.

"The new technique lends itself to multiple applications," said Denise Schach, a postdoctoral fellow in chemistry and co-author of the Optics Express article. "We aim to observe the protein folding process, which is the basis of biological function, inside a single cell." In the future, the new technique might especially benefit research in cellular biology and biomedicine.

Mapping vibrational frequencies

Two-dimensional IR spectroscopy can measure molecular dynamics at the femtosecond (quadrillionth of a second) timescale, which is the vibrational frequency of a chemical bond. The method is used to correlate different vibrational frequencies of a molecule, in order to learn about its structure as well as its chemical environment. Combined with microscopy, the method offers a spatial resolution of 20 microns, about the size of a human skin cell.

"Consider a system of coupled springs: you can pluck one spring and see the energy transfer from this one oscillator to all the other springs in the system," Baiz explained. "It's the same effect with molecules. The laser excites one vibration which then relaxes into other nearby vibrations on the same molecule or its neighbors, and where the vibrational energy ends up tells us about the structure and environment of the molecule."

Multiple factors contributed to the success of Tokmakoff's team, which conducted preliminary experiments for two years at MIT, that enabled the group to plot the best way to develop the new method. Once Tokmakoff joined the UChicago faculty in 2013, his startup funds financed the purchase of the sophisticated and expensive equipment that his team needed to implement the plan.

"The facilities are excellent here" said Baiz, referring to Tokmakoff's laboratory space in the Gordon Center for Integrative Science, which is equipped with stringent temperature and humidity controls, the most technologically advanced optical components, and a brand new microscope.

Also important was the purchase of a new pulse shaper that enabled the researchers to modulate individual laser pulses in a way that traditional optics cannot do, and developing a new way of collecting data that involved a different geometric alignment of the laser beams.

###

Citation: "Ultrafast 2D IR Microscopy," by Carlos R. Baiz, Denise Schach, and Andrei Tokmakoff, Optics Express, Vol. 22, Issue 15, pp. 18724-18735, 2014. http://dx.doi.org/10.1364/OE.22.018724.

Steve Koppes | Eurek Alert!
Further information:
http://www.uchicago.edu

Further reports about: Watching environments frequencies materials skin spatial spectroscopy structure vibrations

More articles from Life Sciences:

nachricht X-ray experiments reveal two different types of water
27.06.2017 | Deutsches Elektronen-Synchrotron DESY

nachricht What Makes Stem Cells into Perfect Allrounders
27.06.2017 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>