Quantum Monte Carlo methods for the surface chemistry of oxide materials

Date & Time
9 November 2005 (Wed), 3:30 pm - 5:00 pm
6F seminar room, Sengen site
Professor M. J. Gillan
Physics and Astronomy Department and London Centre for Nanotechnology, University College London
Quantum Monte Carlo methods for the surface chemistry of oxide materials
Oxide materials are important for many reasons: catalysis, corrosion, gas-sensing, coatings, etc... Density functional theory (DFT) has been used for nearly 15 years to study the energetics and structure of oxide surfaces, and the adsorption and reactions of molecules on these surfaces. However, it has become clear over the past five years that the usual DFT methods are not very accurate or reliable. For example, the adsorption energies of molecules are often in error by up to 0.5 eV (up to 10 kcal/mol). This poor accuracy is not good enough for many practical purposes. This seminar will describe our recent efforts at UCL to apply quantum Monte Carlo techniques (QMC) to these problems. The basic ideas of QMC will be summarised, and examples of their use for small molecules will be shown. Some recent technical developments in basis sets for QMC will then be outlined. Then, the results of our recent QMC calculations on the prototype oxide MgO will be presented, and I will also present our encouraging results on the MgO (001) surface. Finally, I plan to mention preliminary QMC work on the adsorption of the water molecule on the MgO (001) surface.
Dr. Tsuyoshi Miyazaki (宮崎剛)