Dissymmetries in fluorescence excitation and emission from single chiral molecules.

Chirality in molecular systems plays profoundly important roles in chemistry and physics. 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" leading to the "(+)" and "(-)" [or dextrorotatory (d-) and levorotatory (l-)] designations of chiral compounds, with the subsequent determination of absolute stereochemical configuration by chemical or physical means enabling application of the familiar "R" and "S" labels. Although the intrinsic molecular parameters that control the dissymmetric light-matter interaction in chiral systems are well understood, we have only recently begun to ask questions regarding the role of local molecular environment and hidden heterogeneities associated with the ensemble-averaged molecular chiroptical response. In this mini-review, we discuss some of our recent research on application of single-molecule spectroscopy as a tool for probing heterogeneities and fluctuations of chiroptical dissymmetries in condensed phase.