Freezing of a soft-core fluid in a one-dimensional potential: Predictions based on a pressure-balance equation

Abstract

Using concepts from classical density functional theory (DFT) we investigate the freezing of a two-dimensional (2D) system of ultra-soft particles in a one-dimensional (1D) external potential; a phenomenon often called laser-induced freezing (LIF). In the first part of the paper, we present numerical results from free minimization of a mean-field density functional for a system of particles interacting via the GEM-4 potential. We show that the system does indeed display a LIF transition, although the interaction potential is markedly different from the cases studied before. We also show that one may consider the (suitably defined) effective density within the potential wells, ${\bar{\rho }}_{\text{eff}}$, as a control parameter of LIF, rather than the amplitude of the external potential as in the common LIF scenario. In the second part, we suggest a new theoretical description of the onset of LIF which bases on the pressure balance equation relating the pressure tensor and the external potential. Evaluating this equation for the modulated liquid phase at effective density ${\bar{\rho }}_{\text{eff}}$ and combining it with the (known) stability threshold of the corresponding bulk fluid, we can predict the critical effective density or, equivalently, the potential amplitude related to the onset of LIF. Our approach yields very good results for the model at hand, and it is transferable, in principle, to other model systems.

References in corpus (24)

• Can Polymer Coils be modeled as "Soft Colloids"?
• Accurate effective pair potentials for polymer solutions
• Mean Field Fluid Behavior of the Gaussian Core Model
• Exact Criterion for Determining Clustering vs. Reentrant Melting Behavior for Bounded Interaction Potentials
• Fluid and solid phases of the Gaussian core model
• Why do ultrasoft repulsive particles cluster and crystallize? Analytical results from density functional theory
• Freezing and clustering transitions for penetrable spheres
• Computer Assembly of Cluster-Forming Amphiphilic Dendrimers
• Light Induced Melting of Colloidal Crystals in Two Dimensions
• Novel Phases and Reentrant Melting of Two Dimensional Colloidal Crystals
• Microscopically-resolved simulations prove the existence of soft cluster crystals
• An Introduction to Microscopic Theories for Inhomogeneous Liquids: Getting Started with Density Functional Theory
• Solidification in soft-core fluids: disordered solids from fast solidification fronts
• Phase Transitions of Hard Disks in External Periodic Potentials: A Monte Carlo Study
• Hexatic phase and cluster crystals of two-dimensional GEM4 spheres
• Phase Transitions of Soft Disks in External Periodic Potentials: A Monte Carlo Study
• Colloidal suspensions in modulated light fields
• Bond-orientational ordering and shear rigidity in modulated colloidal liquids
• Direct test of defect mediated laser induced melting theory for two dimensional solids
• Laser induced reentrant freezing in two-dimensional attractive colloidal systems
• A numerical renormalization group study of laser induced freezing
• Phase transitions in two-dimensional model colloids in a one-dimensional external potential
• Novel structure formation of a phase separating colloidal fluid in a ratchet potential
• Laser induced freezing of charge stabilized colloidal system

Cited by in corpus (2)

• Freezing and re-entrant melting of hard discs in a one-dimensional potential:\\ Predictions based on a pressure-balance equation
• Freezing of a soft-core fluid in a one-dimensional potential: Appearance of a locked smectic phase