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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: Poster: Charged Soft Matter

CPP 22.18: Poster

Wednesday, March 28, 2012, 11:00–13:00, Poster A

Dielectric spectrum of salt solutions from molecular dynamics simulations — •Marcello Sega¹, Sofia Kantorovich^1,2, 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.