2013 T.K Sidey Medal:Good vibrations for chemistry

Professor McQuillan conducted the first surface-enhanced Raman spectroscopy (SERS) experiments at Southampton University in 1973. Raman spectroscopy is a light scattering technique which is now one of the primary methods used to assess the structure and composition of materials and has found widespread application from drug development to the detection of art forgeries.

In 1928, the Indian scientist Chandrasekhara Raman discovered that when light shines on a molecule, a very small amount of energy is scattered at a different wavelength and this is known as Raman scattering. For any material, the Raman signal is based on the vibrational footprint of the molecule and therefore can be used as an identifying tool. But the Raman signals from the relatively few molecules existing at the surfaces of solids are not easily detected. In surface-enhanced Raman spectroscopy, molecules at the surface of silver nanoparticles have their Raman signals enhanced a million times due to collective free electron oscillations. This extraordinary signal enhancement makes possible the detection of single molecular layers and studies of their surface chemistry. Forty years ago, when Professor McQuillan and colleagues first discovered this technique, they had no idea it would develop into one of the most effective methods of surface analysis in science.

Professor McQuillan has more recently pioneered the use of thin metal oxide particle films deposited on internal reflection prisms to carry out infrared spectroscopic studies of surface chemical reactions. These methods have been used to gain a better understanding of chemical reactions in diverse practical situations such as in titanium dioxide based solar cells and the adhesion of mussel larvae to surfaces.

The in situ spectroscopic methods developed by Professor McQuillan are an outstanding contribution to the study of surface interactions and they have contributed hugely to the understanding of the chemical reactions that take place.

Professor McQuillan is based at the Department of Chemistry at the University of Otago. He was made a Fellow of the Royal Society of New Zealand in 2008. In July 2013, the UK’s Royal Society of Chemistry awarded a National Chemical Landmark blue plaque to the University of Southampton’s Chemistry department in recognition of the discovery of the SERS technique by Professor McQuillan and colleagues.

Citation:

2013 T. K. Sidey Medal

To Alexander James McQuillan

For carrying out the first experiments giving intense Raman scattering from molecules at the surface of silver nanoparticles, known as surface-enhanced Raman scattering (SERS), and for developing infrared spectroscopy to examine the surface chemistry of wet metal oxide nanoparticles.