Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 22: Poster: Charged Soft Matter
CPP 22.18: Poster
Mittwoch, 28. März 2012, 11:00–13:00, Poster A
Dielectric spectrum of salt solutions from molecular dynamics simulations — •Marcello Sega1, Sofia Kantorovich1,2, Axel Arnold1, and Christian Holm1 — 1Institute for Computational Physics, Pfaffenwaldring 27, 70569 Stuttgart, Germany — 2Ural Federal University, Lenin av 51, 620083, Ekaterinburg, Russia
We present the results of MD simulations for water salt solutions with various salt concentrations. Following the experimental approach, we use several fit-functions in order to determine static dielectric permittivities. We show, that the permittivity obtained via Einstein-Helfand fit is extremely sensitive to the statistics and, as a result is very difficult to use reliably. However, the static value of the dielectric permittivity can be evaluated by fitting the complete frequency-dependent spectrum, using, for example, the Cole-Cole relation. We compare our results to the experimental data from [Buchner et al, J. Phys. Chem. A, Vol. 103, 1999, P. 1], which show an initial linear decrease of the static dielectric permittivity as a function of salt concentration, and a saturation at high concentrations.