Quantum Nuclear Effects in Stishovite Crystallization in Shock-Compressed Fused Silica

Abstract

Quantum nuclear effects include zero-point energy for each vibrational mode and potentially significant deviations of the heat capacity from classical values. While these effects play important roles in shock-induced chemical reactions and phase transitions, they are absent in classical atomistic shock simulations. To address this shortcoming, we have studied the quantum nuclear effects for stishovite crystallization in shock-compressed fused silica by employing the quantum bath multiscale shock technique, which couples the shock simulation with a colored-noise Langevin thermostat. We find that this semiclassical approach gives shock temperatures as much as 7% higher than classical simulations near the onset of stishovite crystallization in silica. We have also studied the impact of this approach on the kinetics of stishovite crystallization and the position of high-pressure silica melt line. We further describe a systematic way of setting up the parameters for the quantum thermal bath and quantum bath mu...