Bulk dynamics of Brownian hard disks: Dynamical density functional theory versus experiments on two-dimensional colloidal hard spheres
| Autor: | Daniel Stopper, Roel P. A. Dullens, Roland Roth, Alice L. Thorneywork |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
010304 chemical physics Condensed matter physics Relaxation (NMR) General Physics and Astronomy FOS: Physical sciences Hard spheres Condensed Matter - Soft Condensed Matter Atomic packing factor 01 natural sciences Correlation function (statistical mechanics) 0103 physical sciences Soft Condensed Matter (cond-mat.soft) Density functional theory Physical and Theoretical Chemistry 010306 general physics Particle density Displacement (fluid) Brownian motion |
| Zdroj: | The Journal of chemical physics. 148(10) |
| ISSN: | 1089-7690 |
| Popis: | Using dynamical density functional theory (DDFT), we theoretically study Brownian self-diffusion and structural relaxation of hard disks and compare to experimental results on quasi two-dimensional colloidal hard spheres. To this end, we calculate the self-van Hove correlation function and distinct van Hove correlation function by extending a recently proposed DDFT-approach for three-dimensional systems to two dimensions. We find that the theoretical results for both self-part and distinct part of the van Hove function are in very good quantitative agreement with the experiments up to relatively high fluid packing fractions of roughly 0.60. However, at even higher densities, deviations between the experiment and the theoretical approach become clearly visible. Upon increasing packing fraction, in experiments, the short-time self-diffusive behavior is strongly affected by hydrodynamic effects and leads to a significant decrease in the respective mean-squared displacement. By contrast, and in accordance with previous simulation studies, the present DDFT, which neglects hydrodynamic effects, shows no dependence on the particle density for this quantity. |
| Databáze: | OpenAIRE |
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