Molecular crystals have a wide range of technological uses, from pharmaceuticals to electronic devices. Unfortunately, X-ray diffraction cannot always determine the structures of such materials. Solid-state NMR is an important technique for materials characterisation and could, in principle, be used for structure solution (so call 'NMR Crystallography'). However, there is no simple theory to link the observed NMR spectrum to the underlying atomic level structure (as Bragg's Law does for XRD).
In recent years we have developed computational techniques, based on quantum mechanics, to predict and interpret NMR spectra (see www.gipaw.net). Typically this has focused on the so-call NMR chemical shift, but, excitingly, it has recently become possible to both measure and compute the NMR J-coupling. J-coupling is an indirect interaction of the nuclear magnetic moments mediated by bonding electrons, and provides a direct measure of bond strength and a map of the connectivities of a system (hence its importance for crystallography).
The aim of this DPhil project is to study the nature of NMR J-coupling in molecular crystals - to interpret current experiments, understand the microscopic mechanisms, and guide the development of new experiments. The project is highly computational and will involve the use of large supercomputers, it may (optionally) include the development of new computational methods. The work will be carried out in close collaboration with experimental solid-state NMR studies performed in the group of Dr Steven Brown (University of Warwick).