4-D spectral maps with new detail extracted via a multidimensional coherent spectroscopic method called 'GAMERS,' elucidating subtle effects governing the chemical, physical and optical properties of systems
Researchers at Northwestern University have created a new method to extract the static and dynamic structure of complex chemical systems. In this context, "structure" doesn't just mean the 3-D arrangement of atoms that make up a molecule, but rather time-dependent quantum-mechanical degrees of freedom that dictate the optical, chemical and physical properties of the system.
Consider how we view the world: three dimensions in space and one dimension in time, i.e., space-time. Remove any one of these dimensions and the view becomes incomplete and far more confused. For the same reason, this new method uses four spectral dimensions to resolve structure to reveal hidden features of molecular structure.
In this week's The Journal of Chemical Physics, from AIP Publishing, assistant professor Elad Harel and professor Irving M. Klotz, from the Department of Chemistry at Northwestern University, report a novel 4-D coherent spectroscopic method that directly correlates within and between electronic and vibrational degrees of freedom of complex molecular systems.
Harel's work involves a theoretical description of a recent experimental method developed in his lab, called GRadient-Assisted Multi-dimensional Electronic Raman Spectroscopy, or "GAMERS." It's a multidimensional coherent spectroscopic method in which the dimensions are the electronic and vibrational degrees of freedom of the system.
"Using multiple pulses of light, GAMERS probes how these different degrees of freedom are correlated to one another, creating a sort of spectral map that is unique to each molecule," Harel said. "[I]t demonstrates that subtle effects dictating the chemical, physical, and optical properties of a system, which are normally hidden in lower-order or lower-dimensionality methods, may be extracted by the GAMERS method."
Unlike other methods, this enables a uniquely detailed look at the molecules' energy structure in way that may offer predictive value.
"The shape of the potential surface, which is important for determining the kinetics and thermodynamics of a chemical reaction, may be directly measured," Harel said. "The level of molecular detail afforded by using more pulses of light to interrogate the system was surprising."
One potential application of GAMERS could be to pinpoint the physical mechanism of energy transfer during the earliest stages of photosynthesis, a question that remains controversial among researchers, according to Harel.
Right now, the main application of this work "is to enable insights into the physical mechanisms behind a host of quantum phenomena in a wide variety of chemical systems," Harel said. "These include singlet fission processes, charge carrier generation and transport in hybrid perovskites, and energy transfer in pigment-protein complexes. Understanding these processes has important implications for developing next-generation solar cells."
The GAMERS method is still in an early phase of development, according to Harel, but the team has high hopes for its future application.
"We believe technical advances could make such analysis far more widespread within the chemical physics community," said Harel.
The article, "Four-dimensional coherent electronic Raman spectroscopy," is authored by Elad Harel. The article will appear in The Journal of Chemical Physics April 18, 2017 (DOI: 10.1063/1.4979485). After that date, it can be accessed at http://aip.
ABOUT THE JOURNAL
The Journal of Chemical Physics publishes concise and definitive reports of significant research in the methods and applications of chemical physics. See http://jcp.
Julia Majors | EurekAlert!
IceCube experiment finds Earth can block high-energy particles from nuclear reactions
24.11.2017 | Penn State
New proton record: Researchers measure magnetic moment with greatest possible precision
24.11.2017 | Johannes Gutenberg-Universität Mainz
High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons
The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
24.11.2017 | Physics and Astronomy
24.11.2017 | Health and Medicine
24.11.2017 | Earth Sciences