Research interests of Joseph A. Morrone

Since I took my first chemistry class in college, back in 1999, I became interested in theoretical and computational chemistry, in particular atomic simulation. For those who are not familiar with this field, basically what a computational chemist does is study systems at the atomic level using not lab apparatuses and experiments, but computers running algorithms based on the fundamental laws of physics. In practice, we utilize approximations to these fundamental laws in order to make the problem solvable on a computer. It is our job to formulate these approximate methods, 'code' them into viable computer programs, and then apply the resultant programs to study the properties of various systems of interest, ranging from the exploration of how a molecule binds to a protein, to the structure of a defect in a silicon crystal. The vast majority of my research has centered around hydrogen-bonded systems, in particular water and methanol.

Below you will find a summary of my past work as an undergrad at NYU and a graduate student at Princeton, as well as a list of my publications.

Currently, I am a postdoctoral research scientist in Bruce Berne's group in the Department of Chemistry at Columbia University. I hope to update the site soon with some details of my current research.

Graduate Work

Previously, I was a graduate student in the Department of Chemistry at Princeton University. I was a member of Roberto Car's research group, and I completed my doctorate in July 2008.

This work was centered upon the further development of path integral simulation methodology. Path integral simulations are used in order to describe nuclear quantum effects. Typically in molecular simulation, the nuclei are treated as classical point particles. Nuclear quantum effects are particularly important in the description of hydrogen, since it is the lightest atom and particles tend to behave more ''quantum'' as their mass and temperature decrease. Therefore, nuclear quantum effects can be essential for the understanding of hydrogen-bonding and proton transfer.

To the right is a snapshot of a path integral simulation of water.

Each set of overlapping ''classical'' water molecule coordinates represents one water molecule as described by quantum mechanics. It is quite beautiful that such a simple picture falls out of certain approximations that one can make to the fundamental equations of nature.

There were two primary goals for my work in this area. The first was the development of higher-order path integral algorithms that can both increase the efficiency of the computation, and be utilized to study hydrogen-bonding molecular systems such as water. Some promising results were garnered, and are reported in my dissertation.

Secondly, I was involved in the development of algorithms to compute the proton momentum distribution, which utilize a so-called ''open'' path integral approach. To this end, we have developed an algorithm for ''open'' path integral simulation. This method was first shown to work in conjunction with an empirical potential-based model of water. This methodology has also been implemented in conjunction with first principles (Car-Parrinello) molecular dynamics. First principles open path integral molecular dynamics simulations have been carried out utilizing IBM Blue Gene/L hardware. We have carried out these studies on a variety of phases of water. Please see my dissertation and the work with Roberto Car that is listed in the references for more information.

Undergraduate Work

I also worked under Mark Tuckerman in the Chemistry department at New York University as an undergraduate researcher.

There, I spent three years learning the ropes of Car-Parrinello molecular dynamics, and applying these methods to study methanol (methyl alcohol) in the liquid phase. In the course of my research, we proposed a mechanism for proton transfer in methanol and methanol-water mixtures. Additionally, we created a novel QM/MM (quantum mechanical / molecular mechanic al) potential for the molecule. The figure shown to the the right is a snapshot of a configuration of a molecular dynamics simulation of protonated methanol. The ions and molecules shown as being 'large' are members of the 'defect chain' the species along which proton conduction occurs. Recently, we have also studied proton transport in methanol-water solutions. In the course of this work, we ran simulations of just over 100 picoseconds. This time is one ten billionth of a second. This may not sound like a long time, but with regards to this computationally demanding simulation, it is!

The research interests of Joseph A. Morrone

Graduate Work

Undergraduate Work

Publications