UC Berkeley

An overview of five studies is presented in two parts. The first part presents two studies

of supercooled fluids. The second part presents three studies of water and aqueous solutions.

Each study seeks a minimal model of a condensed matter system. In the first study,

kinetically constrained models (KCM’s) are compared to alternative theories of the glass

transition in high dimensions. Dimensionality is used as a parameter to tune the connectivity

of a lattice, where a higher dimensional model has more interactions between neighboring

sites. This study finds that KCM’s outperform alternative theories in high dimensions. The

second study explores the possibility that bacteria have evolved to exploit the glass transition

to enter a dormant state when environmental conditions are unfavorable. Although the

available evidence shows that the bacterial cytoplasm does not meet the strict definition of a

fragile glass former, much of its behavior is similar to and can be described using close analogies

with the glass transition. In the second part, the third study describes the molecular

mechanisms that gives rise to large electric field fluctuations, which in turn cause autoionization

and ion dissociation. The fourth study analyzes several candidate order parameters

as the basis for a Gaussian field theory of ion solvation. Finally, the fifth study discusses the

most popular current explanation for observed charge asymmetry at liquid-vapor interfaces.

This explanation, based on linear response of the surface polarization to the presence of an

ion, is incorrect. Instead, the surface polarization responds non-linearly to the presence of an

ion. Incorporating these non-linear fluctuations is essential to predict solvation free energies.