Strong short-range attractions in a fluid

• Published in: The Journal of chemical physics 1990-12, Vol.93 (11), p.8220-8227
• Main Authors: HEMMER, P. C, STELL, G
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; General theory of equations of state and phase equilibria; Physics
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.459300

We study the thermodynamics of a one-dimensional fluid with particles interacting via a hard-core pair potential with a deep narrow attractive well plus an infinitely weak and long-ranged attractive tail. The attractive well has a striking effect on the liquid–gas phase boundaries of the pressure–temperature–volume surface that describes the equation of state of the model. This is brought out most clearly by considering the limiting behavior associated with the well width going to zero and the well depth becoming infinite in such a way that the contribution of the well to the second virial coefficient is finite and nonzero at some fixed temperature. Our analysis is primarily classical, but we note the changes to be expected in the quantum description. In particular, we find that when one takes the above limit appropriate to the classical second virial coefficient, no effect at all from the well will be felt when the system is described quantum mechanically.