3 years ago

# Comparison of Single-Ion Molecular Dynamics in Common Solvents.

L. R. Pratt, A. Muralidharan, S. B. Rempe, M. I. Chaudhari

Laying a basis for molecularly specific theory for the mobilities of ions in solutions of practical interest, we report a broad survey of velocity autocorrelation functions (VACFs) of Li$^+$ and PF$_6{}^-$ ions in water, ethylene carbonate, propylene carbonate, and acetonitrile solutions. We extract the memory function, $\gamma(t)$, which characterizes the random forces governing the mobilities of ions. We provide comparisons, controlling for electrolyte concentration and ion-pairing, for van~der~Waals attractive interactions and solvent molecular characteristics. With this model, distinct ion-pairing is noted for LiPF$_6$/ethylene carbonate at 1M concentration. For the heavier ion (PF$_6{}^-$), velocity relaxations are all similar: negative tail relaxations for the VACF and a clear second relaxation for $\gamma\left(t\right)$, observed previously also for other molecular ions and with \emph{n}-pentanol as solvent. For the light Li$^+$ ion, short time-scale oscillatory behavior masks simple, longer time-scale relaxation of $\gamma\left(t\right)$. But the corresponding analysis of the solventberg Li$^+\left(\mathrm{H}_2\mathrm{O}\right)_4$ does conform to the standard picture set by all the PF$_6{}^-$ results.

Publisher URL: http://arxiv.org/abs/1801.07116

DOI: arXiv:1801.07116v1

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.