| Citation | Distinguished for his pioneering development of nuclear magnetic resonance and its application to the solution of a wide range of chemical, physical and biological problems.
Early in his career he observed the first AB4X spin system and he made the first magnetic resonance observation of 93-Nb in solution, thus demonstrating the potential of multinuclear nmr in Chemical Sciences: hitherto, chemically related nmr had been restricted to the observation of protons, fluorine and phosphorus. His analysis of line shapes of spin-1/2 nuclei coupled to central quadrupolar nuclei enabled quantitative measurements of the spin lattice relaxations of the central nuclei in multinuclear molecules and ions to be made: a technique subsequently shown to have wide application. At the outset, he applied the method to the elucidation of the structure and dynamics of solutions of electrolytes: thus, he demonstrated the complex relationship between microscopic dynamics and bulk transport properties in these cases. He was the first in the UK to apply pulsed magnetic field-gradient spin-echo techniques to the investigation of diffusion and flow in liquids. He was the first to determine the distributions of droplet size in emulsions, droplet size being a key factor governing the stability and properties of emulsions of wide importance in biology and industry. He further invented pulse sequences for direct observation of flow properties and demonstrated their utility.
His studies of the underlying mechanism of proton magnetic relaxation in water occurring in biological tissues have significance in medicine: he showed that previous models claiming that water in tissue was solid-like are incorrect. His new model was of great value to subsequent studies of tissue by nmr imaging.
His development of theoretical descriptions of the response of spin systems to pulse sequences was of enabling and general importance in the most recently developed methods of determination of structures of complex molecules.
He was a pioneer in the development and application of high resolution nmr spectroscopy of solids and has used these methods in the study of the structure and properties of a wide range of materials, especially polymers. He has developed nmr methods for the measurement of spatial inhomogeneities in solids and has applied them to the determination of the lamellar crystalline polymers, thuds giving a new insight to their structures and behaviour. |