Classical density functional theory for associating fluids in orienting external fields.
We develop a classical density functional theory (DFT) for two-site associating fluids in spatially homogeneous external fields which exhibit orientational inhomogeneities. The Helmholtz free-energy functional is obtained using Wertheim's thermodynamic perturbation theory and the orientational distribution function is obtained using DFT in the canonical ensemble. It is shown that an orientating field significantly enhances association by ordering the molecules, thereby reducing the entropic penalty of association. It is also shown that association enhances the orientational order for fixed field strength.
Department of Chemical and Biomolecular Engineering, Rice University, 6100 South Main Street, Houston, Texas 77005, USA.
Bennett D
BD
Marshall
Department of Chemical and Biomolecular Engineering, Rice University, 6100 South Main Street, Houston, Texas 77005, USA.
Walter G
WG
Chapman
Centro de Física Teórica e Computacional, Avenida Professor Gama Pinto 2, P-1649-003 Lisbon, Portugal and Departamento de Física, Faculdade de Ciências da Universidade de Lisboa, P-1749-016 Lisbon, Portugal.
Margarida M
MM
Telo da Gama