Transição dinâmica no benzeno supercrítico: insights via dinâmica molecular

Abstract

Fluids whose behavior strictly depends on thermodynamic properties share a common feature, the critical point. Above this point, the fluid exhibits characteristics of both a gas and a liquid, a state known as the supercritical state. Understanding the behavior of supercritical fluids is fundamental and practical importance, as fluids under these conditions become a valuable tool for industry. In this doctoral thesis, we present a study aimed at comprehending the supercritical behavior of benzene using molecular dynamics in the isobaric-isothermal ensemble with a rigid benzene model. This high-pressure study revealed a significant change in the molecular dynamics, an impressive dynamic transition closely linked to the fluid’s properties and the applied temperature. This transition is characterized by low diffusion at low temperatures and a shift to normal fluid diffusion after surpassing the critical temperature. It was observed that this dynamic transition is associated with a decrease in the fluid’s viscosity as the temperature increases. Thus, this study adds a new dimension to our understanding of the molecular behavior of supercritical systems.).