State-of-the-art synchrotron sources around the world provide better possibilities for tracking chemical processes in space and time, according to UK scientist John Evans.

Evans, a chemist at the University of Southampton and the Diamond Light Source, said that 'the opportunities that exist for application of the new brilliant X-ray light sources in chemical problems are enormous.'

He pointed out that so-called 'third generation' synchrotron light sources provide a huge gain in beam intensity compared to conventional laboratory-based instruments. This, said Evans, makes the opportunities for unravelling complex structures and understanding how chemical processes work much greater.

The range of wavelengths available at a synchrotron and the high intensity of the beam mean that a variety of experiments can be carried out quickly and on small samples while prising out extra details, Evans said. This means synchrotron sources can be used to study a wide range of problems. Examples of experiments benefiting from a synchrotron source range from infrared microspectroscopy of Egyptian mummies to X-ray absorption analysis of particles of nuclear fuel found in the vicinity of Chernobyl.

Evans himself is interested in understanding how catalysts work. 'Mostly these are not crystalline, they are either solutions or complex solids,' he explained. 'Time resolved X-ray absorption spectroscopy allows us to identify catalyst structures under operating conditions.' 

His experiments have shown that the structures change during reactions, meaning that any conclusions drawn from starting and finishing structures alone are questionable. 'It is only with these new generation storage ring sources that there is sufficient intensity to achieve these measurements on a relevant timescale,' Evans concluded.

Synchrotron light is produced by accelerating electrons to nearly the speed of light in a storage ring. It consists of radiation spanning the electromagnetic spectrum - from the infrared to X-rays. Third generation synchrotron sources are based around the world, and new sources such as Diamond in the UK, the Australian Synchrotron and SOLEIL in France will soon be operational.

Caroline Moore