Artificial light-harvesting supramolecular structures reproduce the light-to-electrochemical energy transduction mechanisms observed in natural photosynthesis. Among them the prototypical carotenoid(C)−porphyrin(P)− fullerene(C 60 ) type of structures have been the most studied. Several experiments performed in such structures, and others alike, have shown that the photoexcited state C− 1 P−C 60 decays to the metastable charge-separated state C− P •+ −C 60 •− within a few picoseconds, whereas the final charge-separated state, C •+ − P −C 60 •−, is obtained within hundreds of picoseconds. This paper introduces a nonlinear polarizable extended Huckel Hamiltonian that describes the charge dynamics and chargeseparation effects in such triads by means of quantum dynamics simulations performed on the photoexcited electron−hole pair. The results are interpreted on the basis of the discrete self-trapping equation and enlighten the role played by the polarizability on charge-separation phenomena.

In this work, we report on a joint theoretical and experimental investigation on electron-CO 2 collisions in the intermediate energy range. More specifically, the elastic differential, integral and momentum transfer cross sections as well as the grand total (elastic+inelastic) cross sections in the 30-500 eV energy range are calculated and reported. A complex optical potential consisting of static, exchange, correlation-polarization plus absorption contributions is used for the description of the electron-molecule interaction. The Schwinger variational iterative method combined with the distorted-wave approximation is applied to calculate the scattering amplitudes. In addition, experimental absolute elastic differential cross sections generated using the relative flow technique are reported in the 100-400 eV range. Comparison between the calculated results and present measured data and also existing experimental and theoretical results is encouraging.

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The dynamics of photoinduced charge generation is studied for donor−acceptor (D−A) organic interfaces, with focus on the interplay of quantum dynamics, decoherence effects, and recombination. A coarse-grained molecular envelope function model is developed to enable the investigation of large scale D−A heterojunctions, taking into account morphology and molecular orientation as well as the underlying quantum nature of the system. Simulations show that, upon photoexcitation, Frenkel excitons delocalize over several molecules in <300 fs. At the interface, they dissociate without dwelling in intermediate charge transfer states, evincing that exciton motion and dissociation cannot be describe by point particle models. Moreover, as decoherence suppresses the excitonic quantum coherence length, it also decreases the geminate recombination rate. Although ultrafast coherent charge separation is more efficient at early times and, particularly, for excitons created at the interface, diffusion becomes important for excitons created far away from the D−A interface. In this case, decoherence provides a slower but steadier diffusion migration that protects the exciton from geminate recombination. We discuss the balance between charge dissociation and transport in OPV devices and photosynthesis.