Molecular-dynamics simulation of shock-stress-induced amorphization of α-quartz

The molecular-dynamics technique is used to investigate the shock propagation in alpha-quartz using a very long periodic macrocell, and semiempirical long-range Coulomb and short-range interatomic potentials. The equation of state and the phase transformation pressure are in good agreement with published experimental data. The transformed phase is identified to be amorphous, and not as stishovite, and is retained on release of the shock pressure. The Raman A(1) phonon frequency is also simulated successfully which is known to show a significantly different variation with static and shock pressures.