Dynamics, Control and Energy Transfer at Terahertz Frequencies.

Chemical and biological reactions are governed by the coupling of ultrafast chemical events to dynamics on much slower timescales. These ultrafast chemical events often occur at THz frequencies and there is a range of indirect experimental and theoretical evidence to suggest that the coupling of vibrational motion at these frequencies governs the dynamics of a range of reactions across chemistry and biology. In this proposal, enabled by recent technological developments, I will develop a THz multidimensional spectrometer that will be able to measure directly the coupling between these modes on an ultrafast timescale. This will enable me to measure energy transfer between THz frequency modes and the timescales involved therein. Once demonstrated this will be a new, powerful analytical technique with many possible applications. Initial measurements will be performed on two very different material types, the first being energetic materials, and the second, materials that show a dramatic structural change upon illumination by light (a photo-induced phase transition or PIPT). In both materials there is strong indirect experimental and theoretical evidence that the coupling between THz frequency vibrations governs the reaction pathways in these materials. THz multidimensional spectroscopic measurements of these materials will provide the first direct experimental evidence that the coupling between these THz vibrations directly governs the pathway, and dynamics, of a reaction. Once this has been demonstrated, in these two diverse sets of materials, this new analytical technique can be applied to many chemical or biological questions, providing an understanding of reaction dynamics on ultrafast timescales - essentially enabling us to watch chemistry happen. This underlying understanding of reactions dynamics will also underpin the future rational design of materials with tailored physical and chemical properties.
Following on from measuring the coupling between THz modes using THz multidimensional spectroscopy, specifically designed intense THz pulses will then be used to interact directly with this vibrational motion, essentially controlling and steering the chemical dynamics. This control, coupled with the understanding of reaction dynamics and the associated timescales provided directly by THz multidimensional spectroscopy, leads to a method where reactions can be steered and controlled - with huge potential applications. This fellowship will concentrate on three possible applications for THz-driven dynamics, namely (a) the control of enzymatic reactions, (b) the control of solid state phase transformations (concentrating of pharmaceutically relevant polymorphs) and (c) the control of catalytic reactions.

Beneficiaries of this work over the short term (3-5 years) will be mainly academic in nature, which is a necessary step in moving towards non-academic beneficiaries. In particular, the new spectroscopic techniques that I will develop will have a significant impact on the terahertz (THz) and wider ultrafast/multidimensional spectroscopy communities, which are particularly strong within the UK. As the fellowship progresses, the techniques developed and the associated results will be relevant to a cross-disciplinary selection of fields including analytical chemistry, biophysics, reaction dynamics, and free electron laser science. The aim of my impact activities throughout this fellowship will therefore be to disseminate my results to the widest possible audience. To do this the main dissemination route for this proposal will be publication in primary refereed journals with a significant cross-disciplinary readership and by presentations at conferences and workshops that are well attended by a range of academics, SMEs, large companies and government employees.
Industrial beneficiaries in the medium term (5-10 years) will include companies that are interested in the understanding of the initiation and dynamics of reactions involving energetic materials such as the Atomic Weapons Establishment (AWE). In particular the results gained from this fellowship will directly influence the future rational design of more stable, safe energetic materials through control of energy transfer in these materials. I have a track record of working closely with government agencies who are major stakeholders in AWE and would be well placed to increase my impact in this area.
In the longer term (10-25 years), the technology and understanding I will develop as part of this fellowship, and continue to develop beyond the tenure of this programme, has the potential to provide a paradigm shift in the understanding of reaction dynamics in chemistry and biology. Three important areas that I have identified are:
(a) The control and understanding of catalytic reactions;
(b) The control of the formation of pharmaceutical polymorphs;
(c) The development of smart materials.
The areas I have identified are diverse, but a greater understanding of the dynamics of these reactions, coupled with the ability to control them directly, will provide the experimental data needed to design the next generation of such materials. The beneficiaries of such impact would be very broad. It is thought that as much as 90% of all commercially produced chemical products involve catalysts at some stage in the process of their manufacture, thus any information that leads to more efficient, specific catalysts has the potential to improve production and reduce energy consumption across the entire chemical processing industry. In the pharmaceutical industry the development of novel polymorphs and co-crystals is now crucial to the development of new pharmaceutics with the patent landscape of pharmaceutical co-crystals developing rapidly over the previous decade. The potential for new drug discovery by companies such as AstraZeneca and GSK would be significantly increased by the demonstration of control of polymorph formation. Finally, the development of smart materials whose properties can be significantly altered by external stimuli is crucial to the development of new technologies that are interactable, with companies such as Apple, Google and Samsung, along with small technology focussed SMEs all looking for the next technique that provides them with the designing edge in this competitive market.
These are certainly not the only areas where this new technology has the potential to have an impact, however, the connections with academics and industry that I will develop via the network meetings and conferences that I will attend will help me to confirm and develop these areas, while also allowing me to evaluate other high potential and high likelihood impact areas.