First principles prediction of experimental observables

Lead Research Organisation: University of St Andrews
Department Name: Physics and Astronomy

Abstract

It is an exciting time to work at the interface between the atomistic theory of matter and experiment. The gap between the two fields is closing, as improved algorithms and computers allow predictions to be made for ever larger systems, and experimentalists achieve ever finer control over matter. It is now possible to perform calculations, based on the fundamental equations of quantum mechanics and requiring no external parameters, for complex systems which may be considered realistic. The majority of first principles studies result in predictions for the positions of atoms in the material under study, and if these are compared to experiment at all it is to x-ray or neutron diffraction results. Unfortunately, there are many situations where such data does not exist, or is not accurate enough to be useful. My work will ensure that our computational tool-box is not empty when faced with this situation. I will develop, and validate, robust, accurate and ultimately widely available techniques for the calculation of some well chosen experimental observables: Nuclear Magnetic Resonance chemical shifts (their use as an analytical tool is pervasive throughout the physical and biological sciences), Electron Spin Resonance g-tensors (a powerful tool for the identification of paramagnetic defects in solids) and Energy Loss Near Edge Structure (an unparalleled technique for materials characterisation at the atomic scale).