In a project funded by the Chemical Theory, Models, and Computational Methods program of the Chemistry Division, Professor Richard Stratt of Brown University is developing new ways of understanding the complex and seemingly erratic patterns of motion exhibited by molecules in liquids. The immediate goal is to gain insights into the behavior of glass-forming liquids, and liquid crystals. Both of these materials are of enormous technological significance because of their relevance to the manufacture of amorphous materials and to practical display devices. In addition, these methods have potential applications to span an even broader range of chemical problems in solutions. The basic idea is to take advantage of recent progress in using high-performance computation to map out the most favorable molecular pathways. In combination with analysis methods being devised by Professor Stratt and his research group, other scientific groups using ultrafast laser techniques can look for these desired patterns of motion.
The engine driving this effort is that it is now possible to find the geodesic (most efficient) routes through realistic potential energy landscapes of such complex systems as supercooled and mesogenic liquids. But, with the discovery that these routes can be computationally interrogated to discern molecular mechanisms comes the possibility of designing multidimensional spectroscopy experiments to ascertain those mechanisms. The Stratt group will be investigating the specific nonlinear spectroscopic signatures of various kinds of geodesic-defined molecular mechanisms to see if properly chosen spectra can help resolve some of the current mysteries surrounding the dynamics of supercooled fragile liquids and liquid crystals. An integral part of this effort (and part of its broader impact) will be the use of this project as a vehicle for exposing college undergraduates to issues faced in frontline computationally-oriented research. It is hard to overestimate the importance of the United States having an educated citizenry with an appreciation of how such 21st-century scientific methods as computer simulation can be used to approach challenging problems. By focusing on carefully selected portions of the project, undergraduates from a wide variety of different background will be able to gain an appreciation of the challenges and possibilities provided by scientific research.
