Research

One of the challenges in studying aqueous systems is that it is very difficult to visualize all the collective processes that occur on different length scales and time scales. We have recently been trying to understand the properties of the empty-spaces in liquid water under various conditions such as under supercooling as well as in the presence of biological solutes. We have found that the spontaneous fluctuations in water, can create voids which have similar shapes to small hydrophobic polymers. In order to probe the complexity we are using a wide variety of data-science techniques developed in the machine-learning community. The image below shows empty spaces in water showing very similar shapes to those occupied by small polymers.

I am currently part of a Horizon 2020 Consortium funded by the European Commission which is aimed at revolutionizing the design of solar fuels using soap bubbles (http://sofiaproject.eu/). My team is dedicated to developing atomistic models for soap films and providing atomistic insights into the fundamental aspects that will help design more efficient soap films. We are currently working on setting up atomistic simulations of surfactant-water interfaces where we are studying both the dielectric properties as well as the diffusion of gases through the soap film.

The movie on the left shows an atomistic simulation of the C12E6 surfactant in contact with water.

One of the most fundamental processes in acid-base chemistry is the ionization of water, a rare event where a water molecule will spontaneously ionize forming the hydronium and hydroxide ion. Once this process happens, two things can happen: either the ions diffuse away from each other or they recombine forming neutral water again. Although this such a basic reaction that we teach in high school chemistry, the microscopic coordinates and mechanism still remain poorly understood. The movie below shows the recombination of the hydronium and hydroxide ion in water using ab initio simulations.

Recent work from experimental collaborators at Cambridge University in the UK, have shown that amyloid fibrils, which are implicated in numerous diseases, exhibit intrinsic fluorescence upon photo excitation even in the absence of aromatic residues. This is quite surprising. We have recently initiated ab-initio molecular dynamics simulations of this system in an effort to try an understand the molecular and electronic origin of this behavior. The movie below shows an ab initio simulation of the N and C termini of a model amyloid where there is proton transfer going on between the two sites.