Agenda Discussion: Computer Techniques
The previous Agenda Discussions dealt largely with problems and ideas concerned with the construction of atomic potential energy interaction functions (potential functions) and the results of computer experiments on crystal lattice defect properties. In these discussions the primary interest was centered on the intrinsic merit of the potential functions considered and the realism of the results obtained for defect properties based on these potentials. In contrast, the Computer Experiment Techniques session was concerned with the practical aspects of using computer experiments to compute crystal lattice defect properties and to simulate the lattice dynamics behavior of a crystal. The primary interest was focussed on how to perform a computer experiment correctly, given a set of potential functions, rather than on the merit of the potential functions. Said in another way, the primary interest was focussed on how to be certain that one was actually computing what one intended to compute. It is usually easy to compute the properties of a defect that disturbs crystal perfection in a simple and local way because, in this instance , there are only a few possible configuration states and the equilibrium state configuration develops quickly in a simulation of the defect. However, when the defect disturbs the crystal perfection either in a complex way or extensively, then there are usually many possible configuration states with comparable state energies. In these instances it is difficult to be certain that one has indeed simulated the intended equilibrium state, in either a static or a dynamic simulation.
KeywordsComputer Experiment Interstitial Atom Free Boundary Condition Integration Time Step Defect Property
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