Thomas Markland of Stanford University is supported by an award from the Chemical Theory, Models and Computational Methods program to develop techniques to speed up molecular simulations. The particular focus is on transport of protons in complex environments. These simulations include the quantum mechanical nature of the electrons and nuclei that make up the atoms in a molecule. Markland's approach allows for making and breaking chemical bonds as the simulation progresses, which is essential for understanding the transport and chemical reactivity of light atoms such as protons. Proton transport processes in disordered systems are of fundamental importance in systems ranging from chemistry and materials science to geology and biology. These include the elucidation of transport mechanisms in proton exchange membranes used in fuel cells and in biological proton channels, providing insights into their functionality, and how to tune these materials for high efficiency proton transport. Professor Markland is also developing simulation and visualization experiences to improve high school education as well as to encourage more students to study chemistry by hosting high school teachers in his lab. These simulation and visualization experiences aid teachers in implementing scientific exercises that engage students' interest and stimulate them to inquire about the natural world. This is being achieved via partnership with several Stanford outreach programs.
This research is aimed at understanding of the structure and dynamics of proton defects in heterogeneous environments, in concert with the development of approaches to accelerate ab initio path integral molecular dynamics simulations. These methods exploit time- and length-scale separation approaches to increase the efficiency of these simulations based on ring polymer contraction and multiple time-scale molecular dynamics algorithms. Markland and his research group use these approaches to investigate the interplay of structure and dynamics in a wide range of heterogeneous systems containing proton defects ranging from hydrophobic and hydrophilic interfaces to nanoporous systems. These studies are being used to understand how the chemical environment can be tailored to change the transport and reactivity of proton defects
