  We introduce a heterodimer model in which multiple mechanisms of vibronic
coupling and their impact on energy transfer can be explicitly studied. We
consider vibronic coupling that arises through either Franck-Condon activity in
which each site in the heterodimer has a local electron-phonon coupling and as
Herzberg-Teller activity in which the transition dipole moment coupling the
sites has an explicit vibrational mode-dependence. We have computed
two-dimensional electronic-vibrational (2DEV) spectra for this model while
varying the magnitude of these two effects and find that 2DEV spectra contain
static and dynamic signatures of both types of vibronic coupling. Franck-Condon
activity emerges through a change in the observed excitonic structure while
Herzberg-Teller activity is evident in the appearance of significant side-band
transitions that mimic the lower-energy excitonic structure. A comparison of
quantum beating patterns obtained from analysis of the simulated 2DEV spectra
shows that this technique can report on the mechanism of energy transfer,
elucidating a means of experimentally determining the role of specific vibronic
coupling mechanisms in such processes.
