The research in my group uses several different types of lasers (including nanosecond and femtosecond pulsed lasers, and cw lasers) to study chemical reactivity, atmospheric chemistry, methods of trace gas detection, optical properties of aerosol particles, and molecular spectroscopy and photochemistry. We use ultrafast transient absorption spectroscopy to study chemical and photochemical reaction dynamics in liquids, and cavity enhanced spectroscopy methods for a variety of applications in atmospheric chemistry and aerosol science. In addition, we use computational methods such as ab initio electronic structure theory and molecular dynamics to aid the interpretation of experimental measurements. I was the lead investigator on the ERC Advanced Grant CAPRI (Chemical and Photochemical Dynamics of Reactions in Solution, 2012-2017) and my group is part of the EPSRC-funded Programme Grant Ultrafast Photochemical Dynamics in Complex Environments. We also collaborate with Bristol colleagues Prof Jonathan Reid, Prof Dudley Shallcross, Prof Varinder Aggarwal, Dr Tom Oliver, Dr Beatrice Collins, Dr Michael Cotterell and Dr Bryan Bzdek on various of the above research projects.

Further details of my group's research activities can be found at the homepage of the Laser Chemistry, Spectroscopy and Dynamics Group and a full list of my publications is available here.

Our studies of reaction dynamics on ultrafast timescales in liquid solutions were published in Science in 2011. The cover picture shows reaction of CN radicals with cyclohexane in solution in dichloromethane. Theoretical insights from this work were published in 2011 in Nature Chemistry and also featured on the cover.  A paper on F-atom reactions in solution appeared in Science in 2015. 

Professor Orr-Ewing is a supervisor in the EPSRC Centre for Doctoral Training in Chemical Synthesis and the EPSRC Centre for Doctoral Training in Aerosol and Droplet Science.