Critical endpoint and analytical phase diagram of attractive hard-core Yukawa spheres.
We analytically calculate the gas-liquid critical endpoint (cep) for hard spheres with a Yukawa attraction. This cep is a boundary condition for the existence of a liquid. We use an analytical Helmholtz energy expression for the attractive Yukawa (hard) spheres based on the first-order mean spherical approximation to the attractive Yukawa potential by Tang and Lu (J. Chem. Phys. 1993, 99, 9828). This theory and our analytical simplification of it predict the gas-liquid and fluid-solid phase behavior, as found from computer simulations, very accurately as long as the range 1/kappa of attraction is not too short. We find that the cep is situated at kappasigma approximately 6 and at a contact potential around 2 kT. It follows that a liquid state is only possible when the attraction range is longer than (1/6) of the particle diameter sigma, and the attraction strength is smaller than 2 kT. The liquid region does not span more than 0.6 kT in strength, and there is also a relatively narrow window for the attraction range.
Tuinier
Remco
R
Forschungszentrum Jülich, Institut für Festkörperforschung, 52425 Jülich, Germany.t.tuinier@fz-juelich.de
Fleer
Gerard J
GJ
D000465:Algorithms; D002627:Chemistry, Physical / Q000379:methods*; D003102:Colloids / Q000737:chemistry; D003198:Computer Simulation; D015233:Models, Statistical; D010316:Particle Size; D055672:Static Electricity; D013499:Surface Properties; D013816:Thermodynamics
D003102:Colloids