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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 60: Focus: Fundamentals of molecular liquids, ionic liquids and mixtures I

CPP 60.1: Vortrag

Mittwoch, 18. März 2020, 11:30–11:45, ZEU 222

Correlation Length in Concentrated Electrolytes: Insights from All-Atom Molecular Dynamics Simulations — Samuel W. Coles¹, •Chanbum Park^2,3, Rohit Nikam^2,3, Matej Kanduč^2,4, Joachim Dzubiella^2,5, and Benjamin Rotenberg¹ — ¹Sorbonne Université, CNRS, Physicochimie des électrolytes et nanosystèmes interfaciaux, UMR PHENIX, 4 pl. Jussieu, F-75005, Paris, France — ²Research Group for Simulations of Energy Materials, Hahn-Meitner-Platz 1, D-14109, Berlin, Germany — ³Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489, Berlin, Germany — ⁴Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia — ⁵Applied Theoretical Physics-Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Str. 3, D-79104, Freiburg, Germany

We study the correlations length of the charge-charge pair correlations in concentrated electrolyte solutions by means of all-atom, explicit-solvent molecular dynamics simulations. We investigate LiCl and NaI in water, as well as two more complex, molecular electrolyte systems of LiTFSI, in water and in DME/DOL. We observe a Debye-Hückel like regime at low concentration, followed by a minimum reached when d/λ_D ≃ 1, where λ_D is the Debye correlation length and d the effective ionic diameter, and an increasing correlation length with salt concentration in very concentrated electrolytes. As in the experiments, we find that the screening length in the concentrated regime follows a universal scaling law as a function d/λ_D for all studied salts. However, the scaling exponent is significantly lower than the experiments.