An introduction to IR spectroscopy from the Royal Society of Chemistry. Includes vibrational modes of molecules, how an FTIR spectrometer works, what the ATR method is, some spectral interpretation and spectral library matches.
Help figure out what your IR spectrum means with the Infrared Spectrum Song!
Two Berkeley Lab researchers received this year’s Presidential Early Career Award for Scientists and Engineers (PECASE): Christian Bauer (not shown, Physics Division) and Feng Wang of the Materials Sciences Division. Wang is an ALS user on Beamline 1.4 (see ALS Science Highlight Bilayer Graphene Gets a Bandgap and this month's Berkeley Lab News Center article A Whole New Light on Graphene Metamaterials). Wang is cited for “pioneering research on ultrafast optical characterization of carbon nanostructures that has advanced the fundamental understanding of the electronic structure of graphene and is expected to enable the development of advanced-energy-relevant technologies.” PECASE awards are the U.S. government’s highest honors to outstanding scientists and engineers, early in their independent research careers.
Berkeley Lab scientists demonstrate a tunable graphene device, the first tool in a kit for putting terahertz light to work
Long-wavelength terahertz light is invisible – it's at the farthest end of the far infrared – but it's useful for everything from detecting explosives at the airport to designing drugs to diagnosing skin cancer. Now, for the first time, scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley have demonstrated a microscale device made of graphene – the remarkable form of carbon that's only one atom thick – whose strong response to light at terahertz frequencies can be tuned with exquisite precision.
"The heart of our device is an array made of graphene ribbons only millionths of a meter wide," says Feng Wang of Berkeley Lab's Materials Sciences Division, who is also an assistant professor of physics at UC Berkeley, and who led the research team. "By varying the width of the ribbons and the concentration of charge carriers in them, we can control the collective oscillations of electrons in the microribbons."
The name for such collective oscillations of electrons is "plasmons," a word that sounds abstruse but describes effects as familiar as the glowing colors in stained-glass windows.
"Plasmons in high-frequency visible light happen in three-dimensional metal nanostructures," Wang says. The colors of medieval stained glass, for example, result from oscillating collections of electrons on the surfaces of nanoparticles of gold, copper, and other metals, and depend on their size and shape. "But graphene is only one atom thick, and its electrons move in only two dimensions. In 2D systems, plasmons occur at much lower frequencies."
Synchrotron Infrared Microscopy at one of our sister facilities, the Australian Synchrotron.
Synchrotron Infrared Microscopy at one of our sister facilities, the ESRF.
ALS User Proposals