Mutual effect of charge- and number-density correlations in ionic liquids and concentrated electrolytes

Abstract

Correlation functions in concentrated ionic systems are studied within the mesoscopic theory at the level of the Gaussian approximation. The previously neglected fluctuation contribution to the inverse charge-charge correlation function is taken into account to verify the accuracy of the previous results. We calculate the correlation lengths and the amplitudes and show that the fluctuation contribution does not lead to significant changes of the results. We also derive necessary conditions for the presence of both, the oscillatory and the monotonic decays of the charge-charge correlations that must be satisfied by the noncoulombic contributions to the inverse charge-charge correlation function. At the level of the Gaussian approximation, these conditions are not satisfied. Extension of the theory beyond the Gaussian approximation is necessary to verify whether the asymptotic decay of the charge-charge correlations is monotonous or oscillatory, as suggested by the surface force apparatus or by the SAXS experiments, respectively.

14 pages, 5 figures

References in corpus (6)

• The Electrostatic Screening Length in Concentrated Electrolytes Increases with Concentration
• Underscreening in concentrated electrolytes
• Primitive Model Electrolytes in the Near and Far Field: Decay Lengths from DFT and Simulations
• Anomalous Underscreening in the Restricted Primitive Model
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Cited by in corpus (1)

• On the electrical double layer capacitance of the restricted primitive model: a link between the mesoscopic theory and the associative mean spherical approximation