Members of the Fernandez-Serra Group, led by Dr. Alec Wills, were recently featured in a Science Story on the Ookami webpage regarding their recent publication in Physical Review Research:  Anti-Coulomb ion-ion interactions: a theoretical and computational study.

“Picture a dance floor where the usual rules of attraction and repulsion go haywire. In a solvent (like water) like-charged ions (normally wallflowers) decide to dance together, while oppositely charged ions (the usual dance partners) awkwardly avoid each other. This surprising behavior is due to the solvent’s quirky non-local dielectric response function. While this had previously only been linked to a well known phenomenon called ‘overscreening’, researchers from Stony Brook University and the Universidad Autónoma de Madrid have shown that this behavior is always expected whenever a solvent has a sufficiently strong dielectric response.”

Figure: The bound-state depth for dressed-dressed interactions in the TF approximation as a function of its location, colored by the screening parameter . The bound state depth gets weaker with increasing screening length, and the position of the minimum shifts to farther separations. The numerical results agree well with the analytical expressions.