Research Highlights

Foundational Goals

Foundational questions that the Center will address include:

(i) What factors sustain the coherent wave-like properties of excitonic states that direct ultrafast, lossless energy flow?

(ii)  Can coherent phenomena control the production, migration, and delivery of quasi-particles [excitons, polarons, trions (charged excitons)], and thus provide novel opportunities to transfer charge, spin, and excitation via reactions that minimize energy dissipation?

(iii)  Can electronic-vibronic coherence coupled with trion state production enable light-driven reactions that deliver two charges simultaneously?

(iv)  What is the relationship between coherent exciton motion and the subsequent production of a spin-coherent electron-hole pair?

(v)  What factors are important to sustain spin coherence following ultrafast charge separation?

(vi)  Can optical excitation of a donor or acceptor using circularly polarized light create a coherent superposition of excited states that will produce product spin states with yields that depend on the light polarization?

Research Theme: Nanoscale Systems

In this research theme, we aim to: (i) characterize, experimentally and theoretically, coherent phenomena that control production, migration, and delivery of excitons, polarons, trions, and spins; (ii) elucidate designs and environment factors that direct coherent, lossless flow of energy through the nanostructures; (iii) pioneer, using theory and experiment, novel strategies that exploit coherence effects to enable driving the simultaneous delivery of two charges following the absorption of a single photon.

Research Theme: Molecules and Chromophore Aggregate Systems

In this theme, we aim to: (i) understand how symmetry breaking in molecules impacts vibronic coherence; (ii) probe the role of coherent exciton motion in the subsequent production of spin-coherent electron-hole pairs; (iii) elucidate ratcheting schemes, guided by theory, that enable direct coherent, lossless flow of energy; (iv) examine how spin delocalization in an extended π systems controls spin coherence; (v) explore, using theory and experiment, how coherent electronic superposition states carrying angular momentum may impact charge transfer quantum dynamics, (vi) understand the precise role of individual and collective molecular vibrations in enhancing, sustaining or destroying electronic coherence in multi-chromophore aggregates.

The first description of quantum coherence in chemical bonding resides in the Duke University archives, in the form of London’s charge density maps for the triplet and singlet states of the hydrogen molecule, as glorious as when they first appeared in 1928.