Dr. Pascale Changenet, CNRS Palaiseau

Gastgeber: Peter Gilch

"Multiscale conformational dynamics probed by time-resolved circular dichroism"

Circular dichroism (CD) is the property of chiral compounds to differently absorb right and left circularly polarized light. Those signals depends strongly on the organization of their atoms or molecules, making CD a very sensitive probe to their conformation. Coupled with pump-probe techniques, CD spectroscopy allows access to both conformational and electronic structure changes of chiral compounds over very large time scales. However, despite recent technological advances, time-resolved experiments are still poorly developed, as they are subject to many artifacts due to their weak signals (ΔOD = 10^-3-10^-6).
In recent years, we have designed several devices capable of measuring the photoinduced variation of the CD signals of chiral compounds over a time window ranging from a few hundred femtoseconds to seconds. After a brief description of their principle, I will illustrate their application to the measurement of the photoinduced chirality changes of 1,1'-Bi(2-naphthol) derivatives and the folding dynamics of G-quadruplex DNA structures.