Diffusion in inhomogeneous and anisotropic media.

Jørgen Boiden Pedersen (Foredragsholder)

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By studying diffusion in micelles we observed that Monte Carlo calculations did not agree with numerical solutions of the usual diffusion (Smoluchowski) equation when the diffusion coefficient was spatially dependent [1]. This led us to derive the continuous diffusion equation from van Kampen’s general hopping model. The result showed that the usual diffusion equation is correct only for a rather special case and that an alternative form is, in general, more appropriate and agrees with the numerical results. This form of the diffusion equation can be used to describe diffusion in environments where detailed balance does not apply [2]. Unlike the previous form of the diffusion equation the new one can be used for anisotropic and inhomogeneous materials. A covariant version of the equation is particular useful for diffusion on curved manifolds. As a side product of this investigation arose a new and general Monte Carlo method for diffusion in arbitrary environments [3].

[1] M. Christensen and J. Boiden Pedersen, Chemical Physics, 295, 2003, 235—241.
[2] M. Christensen and J. Boiden Pedersen, Journal of Chemical Physics, 119, 2003, 5171—5175.
[3] M. Christensen, Journal of Computational Physics, 201, 2004, 421-438.

Periode26. jul. 201030. jul. 2010
BegivenhedstitelICPAC 2010 International Conference on Pure and Applied Chemistry: null
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