Title:
|
Computational modelling of multiphase catalysis
|
Simulating heterogeneous catalytic processes occurring at solid-liquid interfaces requires
the use of quantum mechanical methods to allow for a description of bond
breaking and bond forming. These methods must also allow a sufficiently sized statistical
sampling of the liquid to be gathered. Current approaches based on density
functional theory (DFT) are too expensive to satisfy these requirements so it is therefore
desirable to develop alternative, faster methods. Self consistent tight binding (TB)
methods, which are derived from a second-order expansion of the Kohn-Sham energy
functional and use a parametrised Hamiltonian matrix, can be significantly faster
than DFT making them ideal for the above task.
In this thesis we describe the development of a TB model for organic molecules
containing carbon, hydrogen and oxygen. This model has been fitted using a combination
of intuition, analytical fitting and genetic optimisation. We have also developed
a framework for the description of inter-molecular Van der Waals interactions using
long-ranged empirical potentials. We have shown that this model is capable of describing
the gas-phase structural and dynamic properties of a range of organic molecules,
as well as the structure and dynamics of liquid-phase alcohols and solvated organic
molecules. We have also shown how the the model can be used to describe chemical
reactions in solution. The model forms part of a larger collection which also includes
models for water and titania. All models within this collection share a single transferable
oxygen species. When combined with a parametrisation of a metal such as
platinum this collection could be used for the study of catalytic processes.
|