Vibronically-induced chirality change in molecules revealed by electronic circular dichroism spectroscopy

A computational study of the vibronically resolved electronic
circular dichroism (ECD) spectra of R-(+)-3-methyl-cyclopentanone,
including both Franck-Condon and Herzberg-Teller contributions,
shows how the latter can introduce a change of sign on the chiral
response of an electronic excited state. This sign inversion
within the vibronically resolved electronic band, which can be
interpreted as a change of the chirality of the system, has in principle
important consequences in comparisons of theoretical and experimental ECD
spectra employed for the assignment of absolute configurations.