Single Molecule Spectroscopy of Chiral Nanosystems: Understanding Heterogeneities in Chiroptical Interactions

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

Chirality, or handedness, associated with molecular systems plays important roles in chemistry, perhaps most notably in biomolecular recognition processes and pharmacological function. Most chemistry students are introduced to the concept of chirality through demonstrations of the interaction of chiral molecules with polarized light manifested as an "optical rotation" (with a well-defined direction and magnitude) which gives rise to the familiar "R" and "S" designations of chiral centers in molecular systems. While the intrinsic molecular parameters that control the dissymmetric light-matter interaction in chiral systems are well understood, the extrinsic factors (coupling to solvent or matrix) remain largely unexplored. The fundamental issue is that much of the detailed information on the influence of local environment on the molecular chiroptical response is obscured through necessary ensemble averaging inherent in conventional (bulk) absorption (circular dichroism) or non-resonant scattering (optical rotatory dispersion) measurements. The principal aim of this project is to use single-molecule chiroptical spectroscopy as a tool for probing the "inhomogeneous broadening" of chiroptical dissymmetry in the condensed phase. This proposed cross-disciplinary research has high fundamental scientific impact and will have a technological impact in the development of advanced display technologies, optical storage devices, and in asymmetric synthesis. The proposed project also serves as an attractive vehicle for broadening the participation and retention of students. Minority and underrepresented students will be recruited for this research project. During summer, two middle or high school students from local area schools will be recruited to participate in this research, thus creating advanced opportunities for pursuing advanced work in science and mathematics. THe group will also increase the interaction between UMass Amherst Chemistry and the middle/high students and science teachers in the Five College area school districts and to provide opportunities for advanced work in science. Such opportunities will help enhance interest in science and mathematics at the middle and high school levels.