NER: Toward Efficient Design Tools for Molecular Machines: Theoretical Investigations of Nanosystems

Drexel University, Philadelphia PA

Investigators

Abstract

0102848 Sohlberg This proposal was received in response to NSE, NSF-0019. Nanotechnology promises engineered devices constructed from just one or a few molecules. Applications are envisioned in medicine, molecular scale electronics, and information gathering for defense, space science, and other extreme environments. Molecular turbines pumping streams of gas one molecule at a time, minuscule valves delivering drugs with unprecedented site and dose specificity, pinhead scale computer disks storing libraries of information, and extremely sensitive artificial olfaction for contraband detection, are all theoretically possible, but first these devices must be designed. The ultimate goal of the program is to develop design engineering tools - "recipes" for nano-devices by design, while simultaneously training tomorrow's engineers and scientists in their development and application. In the case of macroscopic machines, the starting point for the development of engineering models is well known: the Newtonian laws of mechanics and the Maxwellian laws of electricity and magnetism. For molecular systems the starting point is quantum mechanics. Nano-systems exist at the transition/interface between molecular systems, which are dominated by quantum phenomena, and macroscopic systems where matter is essentially continuous and classical physics provides the best description. Modeling this hinterland between the classical and the quantum means incorporating features of both classical and quantum mechanics. Here a program of study is proposed combining semiclassical methods to accurately incorporate classical-quantum correspondence into the description of molecular device mechanics and dynamics, with semiempirical quantum mechanics for efficient structure calculations on these systems. Undergraduate and postdoctoral research assistants will carry out complementary components. Undergraduates will build skills with commercial software for electronic structure calculations while modeling molecular recognition and self-assembly. A postdoctoral research assistant will be involved in the fusion of these methods with the methods of semiclassical mechanics for nano-systems.