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Chemistry Department
Northwestern University

Research Projects in the Schatz Group

The Schatz research group is interested in using theory and computation to describe physical phenomena in a broad range of applications relevant to chemistry, physics, biology and engineering. Among the types of applications that we interested are:

Using theory to model polymer properties in extreme environments (fracture and degradation)

Gas phase reaction dynamics, with applications to combustion and atmospheric chemistry (electronic structure, quantum dynamics, classical and surface hopping dynamics) emphasizing state to state chemistry.

Optical properties of nanoparticles and nanoparticle arrays (classical electrodynamics and electronic structure studies of optical properties).

DNA structure, thermodynamics and dynamics (classical molecular dynamics with bead and atomistic models) particularly concerning DNA melting and electrophoresis.

Modeling Self Assembly and Nanopatterning (classical statistical mechanics and Monte Carlo simulations) including Dip Pen Nanolithography.

Using theory to model polymer properties. This involves electronic structure calculations and molecular dynamics modeling of polymer properties for two applications: erosion of polymers exposed to low earth orbit conditions, and improving polymer mechanical properties using nanocomposites. For a description, click here. Related web site for the erosion project: http://spacematerialsmuri.uchicago.edu or click here for more info

Gas phase reaction dynamics. This research is concerned with the description of chemical reactions, photoprocesses and energy transfer in the gas phase with quantum state resolution. We are especially interested in applications to combustion and atmospheric reactions, and in reactions where there is a change in electronic state during the reaction (nonadiabatic reaction). For a description, click here.

Optical properties of nanoparticles and nanoparticle arrays and aggregates. In this work my group has been developing methods for solving Maxwell's equations for noble metal nanoparticles, especially nonspherical nanoparticles, and arrays and aggregates of nanoparticles. 
We are also developing mixed quantum mechanical/electrodynamics methods for describing the spectroscopic properties of molecules on metal particles.
Optical properties of interest include extinction, scattering, surface enhanced Raman spectroscopy and second harmonic generation. An article which provides a general description of the extinction work is Electrodynamics in Chemistry, by Linlin Zhao et al, in Theory and Applications in Computational Chemistry, Ed. C. Dykstra et al, Wiley, New York, 2005, to be published 

DNA structure, thermodynamics and dynamics. This work is aimed at understanding DNA structure and thermal properties in unusual nanostructured environments. Most of our effort so far has been concerned with DNA melting, especially the change in melting behavior that occurs when DNA is hybridized on the surfaces of gold nanoparticles, linking the particles together. Our original work in this area concerned a bead model for DNA melting: Karen Drukker, Guosheng Wu and George C. Schatz, J. Chem. Phys. 114,579-590 (2001).. More recently we have made important progress in understanding cooperative melting transitions in nanoconfined DNA.  See: What Controls the Melting Properties of DNA-Linked Gold Nanoparticle Assemblies?, Rongchao Jin, Guosheng Wu, Zhi Li, Chad A. Mirkin, and George C. Schatz, J. Am. Chem. Soc., 125, 1643 1654 (2003).

Modeling Self Assembly and Nanopatterning. Here we are studying the self assembly of monomers into ordered structures that occurs either on surfaces or in solution. The surface portion of this project is primarily concerned with dip-pen nanolithography (DPN), which is an approach to nanopatterning in which molecules are deposited on a surface from the end of an AFM tip. Our work on solution self assembly is concerned with the formation of cylindrical micelles from the self-assembly of small peptides.  Recent papers include: How Narrow Can A Meniscus Be?, J. K. Jang, G. C. Schatz and M. A. Ratner, Physical Review Letters, 92, 085504 (2004). ;and All-atom numerical studies of self-assembly of zwitterionic peptide amphiphiles, S. Tsonchev, A. Troisi, G. C. Schatz, M. A. Ratner, J. Phys. Chem. B, in press, 2004.