Science at the Shine Dome 2010

New Fellows Seminar

Wednesday 5 May

Professor Jeffrey Reimers FAA
School of Chemistry, University of Sydney

Jeffrey Reimers obtained his BSc from the Australian National University in 1978 and his PhD on the thermodynamics and spectroscopy of water was awarded by the same institution in 1982. This was followed by three years of postdoctoral study on reaction dynamics and spectroscopy and semiclassical methods in quantum mechanics at the University of California, San Diego. In 1985 he moved to the University of Sydney as an ARC Fellow where he has been ever since. There he has worked very closely with Emeritus Professor Noel Hush and Professor Maxwell Crossley, with a focus on the development of computational methods to design and interpret the properties of complex molecular systems including natural and artificial systems for solar energy conversion, biological systems associated with intelligence, molecular materials and interfaces, molecular electronic technologies, and molecular memory technologies.

Prediction and modelling of the properties of large molecular systems

All chemical reactivity properties, all molecular spectroscopy, and all molecular energy and charge transport properties are controlled by the laws of quantum mechanics. These laws dominate the motions of electrons and often provide critical aspects to the motions of atoms and larger objects. Just as quantum computers can solve problems exponentially better as the computer size increases, quantum processes in molecules require an exponentially increasing amount of computer time as the system gets larger. Understanding biochemical processes and the chemical and physical properties of nanoparticles and supramolecular assemblies involves very large systems – systems many orders of magnitude larger than those for which the quantum equations could be traditionally solved to chemical accuracy. Our work involves the development of new methods, as well as the development of new applications of other’s methods, to make a priori modelling of electronic and nuclear structure a predictive tool for design of biotechnology and nanotechnology. An example is our work that started by quantitatively interpreting the absorption spectrum of the ‘special-pair radical cation’ produced following optical to electrical energy conversion during natural photosynthesis. From the colour of the molecules we were able to predict which mutations of the surrounding protein would best increase the efficiency of the photosynthetic process. Another example is the development of a simple picture-based model for understanding the heating of single molecules trapped in junctions between two nanometre-spaced electrodes.