Berlin 2012 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 16: Poster: Colloids and Complex Liquids
CPP 16.44: Poster
Tuesday, March 27, 2012, 18:15–20:45, Poster A
Disentangling Free-Energy and Diffusivity Contributions of Water Kinetics in Bulk and at Interfaces — •Yann von Hansen1,2, Felix Sedlmeier1, Liang Mengyu1, Dominik Horinek1, and Roland R. Netz1,2 — 1Physik Department, TU München — 2Fachbereich Physik, FU Berlin
We use a recently developed method based on the Fokker-Planck equation [1] to disentangle the contributions of the free energy and diffusivity profiles on the local stochastic dynamics of single water molecules in bulk and at interfaces.
Based on the trajectories of the separation between water molecule pairs from MD simulations, we investigate the bond breakage dynamics in bulk water. From the spectrum of mean first-passage times, the diffusivity profile along the separation coordinate is derived. The six-fold friction increase at small separations and the variations in the diffusivity profiles can be interpreted in terms of a dominant reaction path that involves additional orthogonal coordinates [2].
Using the same methodoly, we study the water kinetics at hydrophobic and hydrophilic substrates and solutes and obtain diffusivity profiles showing significant differences, which can be attributed to the presence of hydrogen bonds [3].
M. Hinczewski et al.,
J. Chem. Phys. 132, 245103 (2010)
Y. von Hansen et al.,
Phys. Rev. E 84, 051501 (2011)
F. Sedlmeier et al.,
J. Stat. Phys. 145, 240-252 (2011)