Thermodynamic and transport properties of triangular-well fluids from molecular dynamics

Abstract

Thermodynamic and transport properties of particles interacting via the triangular-well potential in the range of $1.4\le \lambda \le 2.6$ have been studied using perturbation theory and Molecular Dynamics simulations. We present thermodynamic properties such as vapour-liquid coexistence, vapour pressures, and density for different values of the attractive range potential. Good agreement is observed between the theoretical approach and computer simulations in a wide range of densities, temperatures, and pressures. Additionally, we show Molecular Dynamic simulation results of transport properties such as the self-diffusion coefficient as a function of both density and temperature. Finally, thermodynamic and transport properties of real fluids like oxygen, methane, hydrogen sulfide, and fluoromethane have been predicted using both approaches. Results of vapour-liquid coexistence, vapour pressures, and critical points were in excellent agreement with experimental data. The coupling of perturbation theory, Molecular Dynamics simulations, and the triangular-well pair potential offers a versatile and efficient method to explore various real fluid systems, which would include associating fluids, complex molecular liquids, and colloidal systems. This approach can advance our understanding of these systems using a simple approach and to contribute the development of more accurate and predictive models.

GRAPHICAL ABSTRACT

Keywords:

• Self-diffusion coefficient
• thermodynamic properties
• triangular-well fluid
• molecular dynamics

Acknowledgments

A. T.-C. acknowledges the postdoctoral scholarship granted by CTIC-DGAPA-UNAM (2023). E. A. thanks for the scholarship ‘Jóvenes escribiendo el futuro’ for the financial support. The authors thankfully acknowledge the computer resources, technical expertise, and support provided by the Laboratorio Nacional de Supercómputo del Sureste de México, CONACYT member of the network of national laboratories.

Disclosure statement

No potential conflict of interest was reported by the author(s).