Exploration of approaches to shock-wave simulations

This thesis covers research into a number of atomistic methods for the simulation of shock-waves, most importantly comparisons are drawn between the Hugoniostat method and non-equilibrium molecular dynamics (NEMD),with a view towards removing the limitations of pre-parametrised potentials in atomistic shock-wave studies and enable the capture of more complex phenomena and electronic properties.Simulations were performed on Argon and Silicate structures using standard potentials (the Lennard-Jones and van Beest, Kramer, van Santen (BKS) potentials for Argon and SiO2 respectively) and ab initio approaches.In this work, we present a reparametrisation of the BKS potential, which corrects some of the known flaws of the short-range modification of the BKS potential of Farrow and Probert. We also present algorithms and equations for developments and improvements to the Hugoniostat method including: convergence rate enhancements, methods for elimination of transient states and an automated system for the generation of Hugoniot curves.Further, we demonstrate the benefits of pseudo-equilibrium atomistic simulation to the study of shock-waves, with data obtained from these simulations including detailed local-structure analysis of shocked states of post-shockα-quartz and by applying known approaches of equilibrium molecular dynamics to the pseudo-equilibrium Hugoniostat method such as fluctuation formu-lae to calculate key system properties such as the Gr ̈uneisen parameter in theshocked state.We also attempt to determine the limitations of the Hugoniostat, how far we can stretch the paradigm of reduced system sizes without compromising the validity of the calculation of certain properties.