title: Thermodynamic perturbation theory in fluid statistical mechanics.
abstract: A methodology is proposed that pushes the thermodynamic perturbation theory (TPT) from first order to higher order. The second-order correction is superior to a macroscopic compressibility (MC) approximation of Barker and Henderson. The present third-order TPT performs far better than the original first-order TPT and second-order TPT based on the MC approximation for many subfields in fluid statistical mechanics, such as predicting excess Helmholtz free energy, excess chemical potential, bulk pressure, gas-liquid coexistence, and solid-liquid equilibrium of very short-range potential fluids. A nonuniform version of the TPT is proposed; it is also shown that the nonuniform third-order TPT performs far better than the nonuniform first-order TPT in predicting density profile of fluids in critical region. The present report indicates that the TPT still can be a "universal" and accurate theoretical tool that has general applicability in fluid statistical mechanics, especially in soft-matter physics.
authors.affiliation: Institute of Modern Statistical Mechanics, Hunan University of Technology, Wenhua Road, Zhuzhou City, 412008, P.R. China. chixiayzsq@tom.com
authors.forename: Shiqi
authors.initials: S
authors.lastname: Zhou