Quantum molecular dynamics simulations of thermophysical properties of fluid ethane

TL;DR

This study uses first-principles molecular dynamics to explore the thermophysical properties of fluid ethane under extreme conditions, revealing its equation of state, electronic transitions, and dissociation behavior.

Contribution

It provides new first-principles data on ethane's thermophysical properties and insights into its nonmetal-metal transition and dissociation processes under high pressure and temperature.

Findings

Derived the equation of state for fluid ethane in warm dense conditions.

Identified the correlation between nonmetal-metal transition and dissociation into hydrogen and alkane chains.

Calculated optical conductivity, reflectivity, and electronic structure changes.

Abstract

We have performed first-principles molecular-dynamics simulations based on density-functional theory to study the thermophysical properties of ethane under extreme conditions. We present new results for the equation of state of fluid ethane in the warm dense region. The optical conductivity is calculated via the Kubo-Greenwood formula from which the dc conductivity and optical reflectivity are derived. The close correlation between the nonmetal-metal transition of ethane and its decomposition, that ethane dissociates significantly into molecular and/or atomic hydrogen and some long alkane chains, has been systematically studied by analyzing the optical conductivity spectra, pair correlation functions, electronic density of states and charge density distribution of fluid ethane.