An X-ray Diffractometer for Extreme Conditions Research

We are interested in the effect of pressure on molecular solids. In organic materials pressure modifies and rearranges intermolecular contacts such as hydrogen bonds and van der Waals contacts leading to rich polymorphic diversity. Pressure is thus a very effective tool for exploring the structural flexibility, the so-called 'energy landscapes', of organic solids, a very important factor in the development of pharmaceuticals, which also provides valuable data for computational work such as first-principals prediction of crystal structures.

Changes in primary molecular bond distances tend not to be observed in organic systems at least up to 10 GPa (100 000 atm). By contrast, work on metal coordination compounds has revealed that, unlike organic systems, intramolecular metal-ligand bonding can be affected by pressure. This makes pressure a perfect tool for exploring the relationship between structure and properties in functional coordination materials such as molecular magnets: a material can be studied in different states of distortion, providing the most direct way to study correlations between structure and properties.

The same methodology can be used to study metals, minerals and other extended materials, to show, for example, how rocks change their structures in planetary interiors, how materials can be modified for advanced technological applications and how materials change structure under the influence of shock waves during detonations, and how transport can be made more efficient by controlling the response of additives to the extreme conditions of modern engines.

Pressure can be applied to a sample using a diamond anvil cell, in which a sample is held between the faces of two diamonds. When load is applied to the diamonds, pressure many thousands of times atmospheric pressure can be generated at the sample. The sample can then be studied using single-crystal X-ray diffraction, which is the most precise and convenient way to obtain structural information on the atomic scale, to reveal how the material responds to pressure.

In this project we seek funding for a diffractometer that will enable these studies to be carried out at The Centre for Science at Extreme Conditions, an institute dedicated to extreme conditions research at The University of Edinburgh. The new instrument will be equipped with state-of-the-art detector and X-ray sources, to enable data to be collected very quickly but with high precision. We will design and build new pressure cells which will enable data to be obtained simultaneously at high pressure and variable temperature. The new facility will enable much more complex supramolecular materials to be studied than has hitherto been possible.

The combination of these facilities will provide a unique instrument which enables variation of two fundamentally important thermodynamic variables of temperature and pressure to provide deep insight into the factors which govern phase stability in solid materials.

The principal impacts of this grant will be:

1. Provision of personnel trained to the highest level in advanced experimental techniques, data analysis, the interpretation of disparate data and the communication of the results. These skills are highly transferable and are strengthened by our close links with external partners, including central facilities, research institutes and in the commercial sector. The academic community benefits from the research itself for the reasons summarised in the Academic Beneficiaries section, but also because staff move on to post-doctoral or lectureship positions, where the training can be applied and diversified. Research and development activities in the commercial sector also benefits from highly-trained scientists who often move into strategic management roles as they progress in their careers. The transferability of the skills acquired means that society benefits because scientifically-trained staff who move into careers such as teaching, the environmental sector, engineering and sectors (e.g. finance) which rely on analysis, modelling and interpretation of numerical data. We ensure suitable training in the use of the instrument in a series of training workshops over the course of the grant

2. Provision of unique instrumentation to the UK's research infrastructure. This benefits Academia by providing facilities to develop new research areas, but also a diverse range of industries where a fundamental understanding of the behaviour of solids at extreme conditions is relevant to the development of improved modelling of lubricants, biofuels, energetic materials, phase change materials for energy storage and pharmaceuticals. In addition to training in the use of the instrument described above, we have requested funds for two high-pressure cells which can be provided to new users, ensuring maximum usage and diversification of the science supported.

3. Provision of new research results, to be published in the scientific literature, presented at conferences and included in data-bases. Although interest in application of extreme conditions is growing rapidly, work on complex molecular materials is still a relatively young field with enormous scope for new and disruptive research. This research provides usual data which probes the extremes of inter- and intra-molecular interactions, leading to improved models of the molecular solid state.

4. Provision of opportunities for outreach and public engagement. These include regular hands-on workshops and talks at the annual Edinburgh International Science Festival; attendance at two Royal Society Summer Exhibitions; regular participation in the "I'm a Scientist - Get me out of here!" scheme; and attendance at the annual Midlothian Science Festival as well as visits to schools and community groups. There are also several opportunities throughout the year to show off equipment in CSEC to public audiences through open days and coordinated visits. The centenary of the King's Buildings Campus will be an ideal opportunity for public engagement, and events will include exhibitions and tours. Crystal structures possess eye-catching visual impact, and engage interest in the context of the extreme conditions e.g. of planetary interiors and engineering, and we will continue to exploit links with The Edinburgh College of Art. Training for staff in Public Engagement and Outreach is provided by UoE.