Theory and Modeling

Group Leader: Stephen Gray

An exciting aspect of nanoscience is the close interplay between theory and experiment. In the Theory and Modeling Group, we focus on a number of specific, experimentally relevant areas including, but not limited to, nanocatalysis, nanophotonics, and oxide formation. Our nanocatalysis work seeks to discover the key factors governing catalytic activity of nanoparticles with state-of-the-art electronic structure theory. This work enables, for example, efficient computational screening of large numbers of catalytic materials for which an experimental approach would be prohibitive. Our nanophotonics theory and modeling includes rigorous electrodynamics simulations to understand how light can be effectively manipulated in a variety of nanostructures. This work is of relevance to optoelectronics, chemical sensing, imaging, and solar energy applications.

Research Activities

• Nanocatalysis: Electronic structure calculations are used to elucidate the mechanisms underlying the catalysis of chemical reactions by nanoclusters. For example, we search for nanocatalysts appropriate for renewable energy technologies such as H₂ storage.
• Atomistic studies of nanoscale oxide formation
• Computational nanophotonics: Rigorous electrodynamics calculations, often using the finite-difference time-domain, are undertaken to understand, for example, how complex metallic nanostructures such as metal films with periodic arrays of holes or nanowells, can lead to enhanced spectroscopic responses of relevance to chemical imaging and sensing. Such studies may assist solar energy technologies.
• Dynamics in nanoconfined environments: Molecular dynamics and wave packet calculations of the movement, spectroscopy and reactivity of atoms and molecules in nanoconfined environments such as fullerenes and carbon nanotubes are carried out. We also study energy storage issues such as lithium ion transport in silicon and metal oxide crystal structures.
• Methods and software development: We carry out work on parallelization of density functional theory codes such as G-PAW, as well as other programs such as our quantum and electrodynamics codes. We also work on the development of methods, particularly those that allow us to address the multiscale features of many nanoscience problems.