Rotating light provides indirect look into the nucleus

Nov 30, 2010

Nuclear magnetic resonance (NMR) is one of the best tools for gaining insight into the structure and dynamics of molecules because nuclei in atoms within molecules will behave differently in a variety of chemical environments. Nuclei can be thought of as tiny compasses that align when placed in the field of a strong magnet. Similar to magnetic resonance imaging (MRI), conventional NMR uses short pulses of radio waves to drive nuclei away from equilibrium and a 'signal' emerges as nuclei slowly realign with the field.

Results reported in The Journal of Chemical Physics introduce an alternative path to this information, by using light to observe nuclei indirectly via the orbiting .

"We are not looking at a way to replace the conventional technique but there are a number of applications in which optical detection could provide complementary information," says author Carlos Meriles of the City University of New York.

The new technique is based on Optical Faraday Rotation (OFR), a phenomenon in which the plane of linearly polarized light rotates upon crossing a material immersed in a . When nuclei are sufficiently polarized, the extra magnetic field they produce is 'felt' by the electrons in the sample thus leading to Faraday rotation of their own. Because the interaction between electrons and nuclei depends on the local molecular structure, OFR-detected NMR spectroscopy provides complementary information to conventional detection.

Another interesting facet of the technique is that, unlike conventional NMR, the signal response is proportional to the sample length, but not its volume. "Although we have not yet demonstrated it, our calculations show that we could magnify the signal by creating a very long optical path in a short, thin tube," Meriles says. This signal magnification would use mirrors at both ends of a channel in a microfluidics device to reflect repeatedly through the sample, increasing the signal amplitude with each pass.

Explore further: Experiment with speeding ions verifies relativistic time dilation to new level of precision

More information: The article, "Time-resolved, optically-detected NMR of fluids at high magnetic field" by Daniela Pagliero, Wei Dong, Dimitris Sakellariou, and Carlos A. Meriles appears in The Journal of Chemical Physics. See: link.aip.org/link/jcpsa6/v133/i15/p154505/s1

Provided by American Institute of Physics

4 /5 (3 votes)

Related Stories

Portable High-Resolution NMR Sensor Unveiled

Apr 11, 2005

Homeland security experts may soon be getting a valuable new tool for identifying the chemical constituents in suspicious substances. A portable device makes it possible for the first time ever to take high-resolution ...

'NMR on a chip' features magnetic mini-sensor

Feb 19, 2008

A super-sensitive mini-sensor developed at the National Institute of Standards and Technology can detect nuclear magnetic resonance (NMR) in tiny samples of fluids flowing through a novel microchip. The prototype ...

Hyper-SAGE boosts remote MRI sensitivity

Oct 09, 2009

A new technique in Magnetic Resonance Imaging dubbed "Hyper-SAGE" has the potential to detect ultra low concentrations of clincal targets, such as lung and other cancers. Development of Hyper-SAGE was led ...

First NMR Signal of a Copper Site in Azurin Obtained

Feb 18, 2010

(PhysOrg.com) -- Metalloproteins, such as the copper-containing azurin, play a major role in catalyzing electron transfer in cellular reactions. Understanding how their structure relates to function can give ...

Recommended for you

Uncovering the forbidden side of molecules

2 minutes ago

Researchers at the University of Basel in Switzerland have succeeded in observing the "forbidden" infrared spectrum of a charged molecule for the first time. These extremely weak spectra offer perspectives ...

How Paramecium protozoa claw their way to the top

Sep 19, 2014

The ability to swim upwards – towards the sun and food supplies – is vital for many aquatic microorganisms. Exactly how they are able to differentiate between above and below in often murky waters is ...

User comments : 0