2021/07/16 by Daniel B. Mayer, D. Mayer, Erick Sarmiento‐Gómez +6
Biochemistry, Genetics and Molecular Biology · Chemistry · Engineering · Materials Science · Mathematics · Physics and Astronomy · #Advanced Fluorescence Microscopy Techniques #Anisotropic diffusion #Anisotropy #Brownian motion #Chemistry #Classical mechanics #Condensed matter physics #Diffusion #Dimer #Field-Flow Fractionation Techniques #Geometry #Material Dynamics and Properties #Mathematics #Molecular physics #Nuclear magnetic resonance #Optics #Particle (ecology) #Perpendicular #Physics #Quantum mechanics #Relaxation (psychology) #Rotational diffusion #Scattering #cond-mat.soft
paper · pdf · doi:10.1103/physreve.104.014605
published as Phys. Rev. E 104, 014605 (2021)
openalex publication_date 2021/07/16 · arxiv created 2021/08/02 · arxiv updated 2021/08/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the two-dimensional motion of colloidal dimers by single-particle tracking and compare the experimental observations obtained by bright-field microscopy to theoretical predictions for anisotropic diffusion. The comparison is based on the mean-square displacements in the laboratory and particle frame as well as generalizations of the self-intermediate scattering functions, which provide insights into the rotational dynamics of the dimer. The diffusional anisotropy leads to a measurable translational-rotational coupling that becomes most prominent by aligning the coordinate system with the initial orientation of the particles. In particular, we find a splitting of the time-dependent diffusion coefficients parallel and perpendicular to the long axis of the dimer which decays over the orientational relaxation time. Deviations of the self-intermediate scattering functions from pure exponential relaxation are small but can be resolved experimentally. The theoretical predictions and experimental results agree quantitatively.