ADVERTISEMENT
2 /3 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Analytical Chemistry

New Raman Method Measures Extremely Low Frequency Acoustic Vibrations

Spectra reveal information about the size, shape, and mechanical properties of nanoparticles and proteins

by Celia Henry Arnaud
December 1, 2014 | APPEARED IN VOLUME 92, ISSUE 48

[+]Enlarge
Credit: Nat. Photonics
Two laser beams combine to generate a “beat frequency” that excites low-frequency Raman-active vibrations in nanoparticles and proteins.
09248-scicon-NatPhotFigure1.jpg
Credit: Nat. Photonics
Two laser beams combine to generate a “beat frequency” that excites low-frequency Raman-active vibrations in nanoparticles and proteins.

A new acoustic method allows researchers to obtain Raman spectra of low-frequency vibrational modes that are not usually accessible to the analytical technique. Reuven Gordon, Skyler Wheaton, and Ryan M. Gelfand of the University of Victoria, in British Columbia, call the new method extraordinary acoustic Raman, or EAR (Nat. Photonics 2014, DOI: 10.1038/nphoton.2014.283). To obtain the spectra, they combine the beams from two lasers at slightly different wavelengths to generate a “beat frequency” that modulates the electric field in laser tweezers holding a nanoparticle or protein in place. The modulation excites Raman-active vibrations that cause mechanical stretching in the particle or protein. These vibrations provide information about the size, shape, and mechanical properties of the sample. In the case of proteins, the spectra could be used to study phenomena such as allostery, in which ligand binding at one site causes conformational changes that affect binding sites elsewhere.

X

Article:

This article has been sent to the following recipient:

Leave A Comment

*Required to comment