Abstract

The solvation of ions in water plays an important role in numerous processes, such as the denaturing of proteins, electrochemical reactions and desalination. Despite being studied extensively for more than a century, even the simplest process — the solvation of a small spherical ion in water — is still a challenge for theory. For example, it is observed empirically that anions tend to be solvated much more favorably than cations of a similar size, a phenomenon that is not captured by standard dielectric continuum theories (DCT). In this talk, I will show that a suitably constrained quadrupole field (in addition to the dipole field that is usually modeled by DCT ) can lead to a simple theory resembling the Born model that accurately describes aqueous ion solvation.