Effective structure of a system with continuous polydispersity

Abstract

In a system of N particles, with continuous size polydispersity there exists N(N-1) number of partial structure factors making it analytically less tractable. A common practice is to treat the system as an effective one component system which is known to exhibit an artificial softening of the structure. The aim of this study is to describe the system in terms of M pseudo species such that we can avoid this artificial softening but at the same time have a value of M << N. We use potential energy and pair excess entropy to estimate an optimum number of species, M_{0}. We find that systems with polydispersity width, Δσ_{0} can be treated as a monodisperse system. We show that M_{0} depends on the degree and type of polydispersity and also on the nature of the interaction potential, whereas, Δσ_{0} weakly depends on the type of the polydispersity, but shows a stronger dependence on the type of interaction potential. Systems with softer interaction potential have a higher tolerance with respect to polydispersity. Interestingly, M_{0} is independent of system size, making this study more relevant for bigger systems. Our study reveals that even 1% polydispersity cannot be treated as an effective monodisperse system. Thus while studying the role of polydispersity by using the structure of an effective one component system care must be taken in decoupling the role of polydispersity from that of the artificial softening of the structure.

12 pages, 15 figures, 2 tables

References in corpus (20)

• Models and algorithms for the next generation of glass transition studies
• Structural relaxation of polydisperse hard spheres: comparison of the mode-coupling theory to a Langevin dynamics simulation
• Relationship between thermodynamics and dynamics of supercooled liquids
• The role of structure and entropy in determining differences in dynamics for glass formers with different interaction potentials
• Dependence of the fragility of a glass former on the softness of interparticle interactions
• The Static Lengthscale Characterizing the Glass Transition at Lower Temperatures
• Equilibrium glassy phase in a polydisperse hard sphere system
• Evaluation of phenomenological one-phase criteria for the melting and freezing of softly repulsive particles
• Energy Landscape, Anti-Plasticization and Polydispersity Induced Crossover of Heterogeneity in Supercooled Polydisperse Liquids
• Does the configurational entropy of polydisperse particles exist?
• Unraveling the success and failure of mode coupling theory from consideration of entropy
• Determination of onset temperature from the entropy for fragile to strong liquids
• A Microscopic Theory of Softness in Supercooled Liquids
• Impact of size polydispersity on the nature of Lennard-Jones liquids
• The role of pair correlation function in the dynamical transition predicted by the mode coupling theory
• Effect of total and pair configurational entropy in determining dynamics of supercooled liquids over a range of densities
• Implications of the effective one-component analysis of pair correlations in colloidal fluids with polydispersity
• Influence of mass polydispersity on dynamics of simple liquids and colloids
• A Comparative Study of a Class of Mean Field Theories of the Glass Transition
• Analysis of the anomalous mean field like properties of Gaussian core model in terms of entropy

Cited by in corpus (3)

• Dimensionality reduction of local structure in glassy binary mixtures
• Dynamic heterogeneity in polydisperse systems: A comparative study of the role of local structural order parameter and particle size
• Thermodynamics and its correlation with dynamics in a mean-field model and pinned systems: A comparative study using two different methods of entropy calculation