The thermodynamics of heteronuclear molecules formed from bonded square-well (BSW) segments using the SAFT-VR approach

Abstract

We broaden the scope of the statistical associating fluid theory for potentials of variable attractive range (SAFT-VR) to treat heteron uclear chain molecules formed from bonded square-well (BSW) segments. The ideas of the bonded hard sphere (BHS) treatment for distributed-site models composed of hard-sphere segments are applied to square-well sites with the SAFT-VR approach. The results of isothermal—isobaric Monte Carlo simulations are reported for heteronuclear square-well diatomics with different sets of energy and range parameters. The SAFT-VR approach provides an excellent description of the equation of state of the diatomic systems for a wide range of densities. The goal of the work is to provide a rigorous treatment of distributed-site models of fluids, and to establish a framework for a group contribution approach with SAFT-VR.