Perturbative theoretical model of electronic transient circular dichroism spectroscopy of molecular aggregates

A chiral analog of transient absorption spectroscopy, transient circular dichroism (TCD) spectroscopy is an emerging time-resolved method. Both spectroscopic methods can probe the electronic transitions of a sample, and TCD is additionally sensitive to the dynamic aspects of chirality, such as those induced by molecular excitons. Here, we develop a theoretical description of TCD for electronic multi-level models in which the pump pulse is linearly polarized and probe pulse is alternately left- and right-circularly polarized. We derive effective response functions analogous to those often used to describe other four-wave mixing methods and then simulate and analyze TCD spectra for three representative multi-level electronic model systems. We elaborate on the presence and detection of the spectral signatures of electronic coherences.

Automated summary

Transient circular dichroism (TCD) spectroscopy is an emerging time-resolved method that can probe the electronic transitions and dynamic aspects of chirality. In this study, the authors develop a theoretical description of TCD for electronic multi-level models and simulate and analyze TCD spectra for three representative model systems. The presence and detection of spectral signatures of electronic coherences are discussed in detail.