Chemistry on Ultrafast and Small Domains

Many chemical processes occur on ultrafast (femtosecond, picosecond and nanosecond) time-scales. Molecular motion and conformational changes, energy and electron redistribution within and between molecules and excited state dynamics are examples of such processes. Ultra-short pulsed lasers offer a unique window into the dynamics of these ultrafast processes. Our research interests centre around the development and use of ultrafast laser spectroscopic techniques that are applied to the study of photophysical processes occurring in macroand supra-molecular systems. Some of these methods involve the use of multiple femtosecond pulses whereby one pulse induces a shortlived chemical change and subsequent pulses are used to probe the dynamics of that change.

There is also a need to investigate chemical processes on small domains. We can carry out fluorescence spectroscopic measurements at very high spatial resolution (~10s of nanometres, through scanning near field optical microscopy), high spectral resolution, and at the single photon and single molecule levels of sensitivity. These techniques are being applied to the study of systems such as luminescent polymers and particles.

One key area of research is the development of methods combining ultra-short lasers with microscopy techniques to allow the study of chemical processes on short time and small size domains. We have developed time-resolved confocal and two-photon fluorescence microscopy methods, which are used to determine the localisation of different fluorescent species in conjugated, aromatic and bio-polymer systems, with picosecond temporal and sub-micrometre spatial resolution. We are also investigating the behaviour of synthetic and bio-polymers in the region around a solid/liquid interface, using novel timeresolved total internal reflection fluorescence methods.

For further information visit the photophysics and photochemistry research page.