Conclusions and Future Work

To conclude, a kinetic Monte Carlo code has been developed and has been used in validation studies on several interatomic potentials. The following provides a brief summary of the conclusions drawn from this study:

1. A generalized Kinetic Monte Carlo code has been developed to simulate diffusion of defects whose migration energies can vary according to arbitrarily specified local atomic configurations.
2. The Molecular Dynamics code GULP has been used to calculate local configuration dependent migration energies from three different interatomic potentials for lanthanum doped ceria.
3. Kinetic Monte Carlo simulations have been carried out on oxygen vacancy diffusion in lanthanum doped ceria.
4. The lanthanum trapping effect in lanthanum doped ceria has been confirmed both from Molecular Dynamics results and from Kinetic Monte Carlo results.
5. Diffusion results from three different interatomic potentials have been compared to each other and to experimental activation energy data.

There are also some places for improvement and extension in the KMC simulation and the generalized KMC code. The following provides a brief list of possible future work:

• Neighbor tables could be added to each Entity that would contain the atoms that that could be affected by a migration event. This would allow the Event catalog to be selectively modified at the end of each time step instead of being completely rebuilt.
• Oxygen vacancies have a tendency to cluster and form voids. A similar series of Molecular Dynamics calculations could be performed on vacancy-vacancy interactions and these interactions could be added to the simulation.
• Support for additional event types such as particle production (e.g. as a result of radiation damage or fission events) or particle recombination (e.g. Frenkel pair recombination) could be added.
• The use of memory pointers makes parallelization in non-shared memory paradigms difficult. Alternatives that require more work and bookkeeping could be considered in an effort to allow parallelization.