title: Diffusion of Small Solute Particles in Viscous Liquids: Cage Diffusion, a Result of Decoupling of Solute-Solvent Dynamics, Leads to Amplification of Solute Diffusion.
abstract: We study the diffusion of small solute particles through solvent by keeping the solute-solvent interaction repulsive and varying the solvent properties. The study involves computer simulations, development of a new model to describe diffusion of small solutes in a solvent, and also mode coupling theory (MCT) calculations. In a viscous solvent, a small solute diffuses via coupling to the solvent hydrodynamic modes and also through the transient cages formed by the solvent. The model developed can estimate the independent contributions from these two different channels of diffusion. Although the solute diffusion in all the systems shows an amplification, the degree of it increases with solvent viscosity. The model correctly predicts that when the solvent viscosity is high, the solute primarily diffuses by exploiting the solvent cages. In such a scenario the MCT diffusion performed for a static solvent provides a correct estimation of the cage diffusion.
authors.affiliation: Polymer Science and Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, India.
authors.forename: Sayantan
authors.initials: S
authors.lastname: Acharya
authors.affiliation: Polymer Science and Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, India.
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Nandi
authors.affiliation: Polymer Science and Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, India.
authors.forename: Arkajit
authors.initials: A
authors.lastname: Mandal
authors.affiliation: Polymer Science and Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, India.
authors.forename: Sucharita
authors.initials: S
authors.lastname: Sarkar
authors.affiliation: Polymer Science and Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, India.
authors.forename: Sarika Maitra
authors.initials: SM
authors.lastname: Bhattacharyya
mesh_terms: D004058:Diffusion; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D010316:Particle Size; D012996:Solutions; D012997:Solvents / Q000737:chemistry*; D014783:Viscosity
chemical_list: D012996:Solutions; D012997:Solvents