Towards chemical accuracy for molecular processes on oxide surfaces

4 February 2008 (Mon), 3:30 pm - 5:00 pm

8F larger seminar room, Sengen site

Professor M. J. Gillan

Materials Simulation Laboragtory, London Centre for Nanotechnology, Department of Physics and Astronomy, University College London, UK

Towards chemical accuracy for molecular processes on oxide surfaces

Density functional theory (DFT) is widely used for studying the energetics of molecular processes on surfaces, but for oxide surfaces its accuracy leaves much to be desired. For example, the adsorption energy of the H2O molecule on the MgO (001) surface calculated with different exchange-correlation functionals varies by over 0.5 eV. It is clear that DFT calculations for such systems need to be calibrated against more systematic and accurate methods, which should themselves be checked against experimental measurements. Taking H2O on MgO (001) as an example, I will show how both quantum Monte Carlo (QMC) calculations and high-level quantum chemistry methods can be used to place constraints on the errors of DFT calculations. I will also outline how statistical-mechanical calculations of the absolute molecular desorption rate, compared with the results of temperature programmed desorption experiments, can provide another way of assessing DFT errors. The future possibility of statistical-mechanical calculations based on QMC or high-level quantum chemistry will be indicated.

Dr. Tsuyoshi Miyazaki (宮崎剛)