Dresden 2011 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 10: Posters I
DY 10.18: Poster
Montag, 14. März 2011, 17:00–19:00, P4
General relation between signal attenuation from gradient nuclear magnetic resonance and distribution of diffusivities from single-molecule tracking in diffusion processes — •Michael Bauer1, Günter Radons1, Rustem Valiullin2, and Kärger Jörg2 — 1Chemnitz University of Technology, Germany — 2University of Leipzig, Germany
Diffusion processes in heterogeneous environments appear in many physical and biological applications, for instance in ultra-thin liquid films. Liquid layering leads to a change of diffusion properties and induces heterogeneities in the observed motion of tracer molecules. In order to characterize processes observed by single-molecule tracking (SMT) we suggested to investigate the distribution of diffusivities and their dependence on observation time [1]. This technique provides advantages over conventional methods such as mean-squared displacements, which conceal the effects of inhomogeneities. In our contribution we extend the investigations to ensemble-based measurements obtained from pulsed field gradient nuclear magnetic resonance (PFG NMR). Our objective is to relate the signal attenuation of PFG NMR, which corresponds to the propagator in Fourier space, to the distribution of diffusivities [2]. We derive analytical expressions and illustrate the applicability of this approach by the well-established two-region exchange model known from PFG NMR studies. Furthermore, our method provides a promising approach to investigate ergodicity of such systems.
[1] M. Bauer et al., diffusion-fundamentals.org 11, 104 (2009)
[2] M. Bauer et al., J. Chem. Phys., submitted (2010)