A multimodal screening length analysis of concentrated electrolytes

Fourier analysis revealed that there are many modes present in the radial charge density. For all electrolytes considered at low concentrations the dominant mode was a non-oscillatory Yukawa decay mode, while at higher concentrations modes with non-zero spatial frequencies dominated. Resulting screening modes with oscillatory wavelengths ∼5-15 Å from Prony's method agree with the largest experimental screening lengths from surface force apparatus and fluorescence experiments. Concurrently, screening lengths with shorter oscillatory wavelengths, 3-5 Å, have smaller magnitudes and agree with other experiments such as atomic force microscopy and optical second harmonic scattering experiments.