Proposed Research

NMR chemical shifts In collaboration with Prof. Mauri in Paris, I have developed a pseudopotential theory for the calculation of NMR chemical shifts in periodic solids.[2] This is based on Mauri's solution to the gauge invariance problem in extended systems and combined with a projector augmented wave (PAW) approach similar to that used in my scheme for the calculation of ELNES. We can currently reproduce the results of traditional chemists approaches for small molecules, with considerably less computational effort. Since it is based on the planewave pseudopotential method, we can ensure complete convergence with respect to the basis set. We expect to apply the final method to the interpretation of NMR chemical shift in complex minerals, and to study Si/Al disorder. We will also apply the technique to large scale biological molecules. This is currently proceeding in collaboration with Prof. Sanders group in the Chemistry Department.

O(N) Soon I will begin a collaboration Peter Haynes of TCM, Cavendish Laboratory. We intend to develop a total energy code (similar in functionality to the CASTEP code) whose computational cost scales in proportion to the number of atoms in the system, as opposed to as the square or cube. Developing such a code is essential if these first principles techniques are ever to be applicable to, for example, the modelling of crack propagation in brittle materials or to biochemical reactions.