Microscopic properties of nanopore water from its time-dependent dielectric response.
We present a simple kinetic model for the orientational dynamics of a chain of hydrogen-bonded molecules due to the diffusion of orientational defects. We derive an event-driven algorithm which allows us to do kinetic simulations for chains from nanoscopic to macroscopic lengths, spanning huge orders of magnitude in time. Our simulations and analytical calculations show that nanopore water exhibits Debye behavior arising from the diffusive dynamics of orientational defects. For the limits of short and long chains we derive analytical expressions for the relaxation times which allow to extract the diffusion constant, the effective interaction, and the excitation energy of these defects from dielectric spectroscopy experiments. We also discuss the possibility to use such experiments to detect if the two possible kinds of orientational defects differ in excitation energy and diffusion constant.
Laboratory of Chemical Physics, Bldg. 5, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, 20892.
Jürgen
J
Köfinger
Christoph
C
Dellago