Molecular dynamics simulations of weak detonations

Abstract

Detonation of a three-dimensional reactive nonisotropic molecular crystal is modeled using molecular dynamics simulations. The detonation process is initiated by an impulse, followed by the creation of a stable fast reactive shock wave. The terminal shock velocity is independent of the initiation conditions. Further analysis shows supersonic propagation decoupled from the dynamics of the decomposed material left behind the shock front. The dependence of the shock velocity on crystal nonlinear compressibility resembles solitary behavior. These properties categorize the phenomena as a weak detonation. The dependence of the detonation wave on microscopic potential parameters was investigated. An increase in detonation velocity with the reaction exothermicity reaching a saturation value is observed. In all other respects the model crystal exhibits typical properties of a molecular crystal.

Mechanism of Intact Adsorbed Molecules Ejection Using High Intensity Laser Pulses

“…This momentum transfer across the molecular layer resembles soliton like propagation. 26 Once the soliton like wave reaches the molecular layer edge, part of it is reflected back from the molecular layer−gas interface and the remaining part causes ejection of molecules and/or clusters into the gas phase. Collisions between molecules at neighboring layers lead to the characteristic velocity distribution after ejection.…”

“…The momentum acquired by the molecular layer at the substrate–adsorbate interface, due to the initial impulse, propagates across the molecular multilayer almost without dissipation with nearly constant velocity. This momentum transfer across the molecular layer resembles soliton like propagation . Once the soliton like wave reaches the molecular layer edge, part of it is reflected back from the molecular layer–gas interface and the remaining part causes ejection of molecules and/or clusters into the gas phase.…”