Coherences among excited states report on interactions between electronic states and their environment. Specifically, these signals report on precisely the bath motions that can couple energy transfer between the states. Mixed electronic-vibrational (vibronic) resonance has been proposed as a possible physical origin for the prolonged lifetimes of coherences observed in some systems, and recent observations confirm the existence of vibronic coupling in both model systems and photosynthetic complexes. Establishing control over this vibronic coupling will permit unambiguous identification of detailed molecular design principles that control the interplay between vibronic coupling and energy transfer. I will discuss a series of structurally flexible synthetic heterodimers can be packed on single-walled carbon nanotubes (SWNT), which fixes spatial relationships among chromophores. Only then, does a distinct quantum beating signature appear. Utilizing two-dimensional electronic spectroscopy (2DES), we find that a fixed spatial relationship and a vibrational mode in resonance with a higher energy electronic excited state are two key factors to engineer vibronic coherence in artificial systems.

Probing and understanding quantum beating signals in rigid heterodimers with 2D spectroscopy

251st National Meeting (2016)

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