title: Communication: translational Brownian motion for particles of arbitrary shape.
abstract: A single Brownian particle of arbitrary shape is considered. The time-dependent translational mean square displacement W(t) of a reference point at this particle is evaluated from the Smoluchowski equation. It is shown that at times larger than the characteristic time scale of the rotational Brownian relaxation, the slope of W(t) becomes independent of the choice of a reference point. Moreover, it is proved that in the long-time limit, the slope of W(t) is determined uniquely by the trace of the translational-translational mobility matrix μ(tt) evaluated with respect to the hydrodynamic center of mobility. The result is applicable to dynamic light scattering measurements, which indeed are performed in the long-time limit.
authors.affiliation: Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Hoża 69, 00-681 Warsaw, Poland.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Cichocki
authors.forename: Maria L
authors.initials: ML
authors.lastname: Ekiel-Jeżewska
authors.forename: Eligiusz
authors.initials: E
authors.lastname: Wajnryb
mesh_terms: D004058:Diffusion; D008962:Models, Theoretical; D009038:Motion