TY - JOUR

T1 - Phase lines in mean-field models with nonuniform external forces

AU - Kroll, Roni

AU - Tsori, Yoav

N1 - Funding Information:
This work was supported by the Israel Science Foundation (ISF) Grant No. 274/19.
Publisher Copyright:
© 2022 Author(s).

PY - 2022/12/21

Y1 - 2022/12/21

N2 - We look at the influence of external fields on systems described by generic free energy functional of the order parameter. The external force may have arbitrary spatial dependence, and the order parameter coupling may be nonlinear. The treatment generalizes seemingly disparate works, such as pure fluids, liquid and polymer mixtures, lipid monolayers, and colloidal suspensions in electric fields, fluids, and nematics in gravity, solutions in an ultracentrifuge, and liquid mixtures in laser radiation. The phase lines and thermodynamic behavior are calculated at the mean-field level. We find a "surface"critical point that can be shifted to higher or lower temperatures than the bulk critical point. Below this point, the transition from a "gas"phase to a "liquid"phase is first-order, while above it, the transition is second-order. The second-order line is affected by the spatial dependence of the force, while the first-order line is universal. Moreover, the susceptibility may diverge at a finite location r. Several analytical expressions are given in the limit where a Landau expansion of the free energy is valid.

AB - We look at the influence of external fields on systems described by generic free energy functional of the order parameter. The external force may have arbitrary spatial dependence, and the order parameter coupling may be nonlinear. The treatment generalizes seemingly disparate works, such as pure fluids, liquid and polymer mixtures, lipid monolayers, and colloidal suspensions in electric fields, fluids, and nematics in gravity, solutions in an ultracentrifuge, and liquid mixtures in laser radiation. The phase lines and thermodynamic behavior are calculated at the mean-field level. We find a "surface"critical point that can be shifted to higher or lower temperatures than the bulk critical point. Below this point, the transition from a "gas"phase to a "liquid"phase is first-order, while above it, the transition is second-order. The second-order line is affected by the spatial dependence of the force, while the first-order line is universal. Moreover, the susceptibility may diverge at a finite location r. Several analytical expressions are given in the limit where a Landau expansion of the free energy is valid.

UR - http://www.scopus.com/inward/record.url?scp=85144571007&partnerID=8YFLogxK

U2 - 10.1063/5.0129110

DO - 10.1063/5.0129110

M3 - Article

C2 - 36550037

AN - SCOPUS:85144571007

SN - 0021-9606

VL - 157

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

IS - 23

M1 - 231103

ER -