INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Quantum dynamics simulations of photoinduced charge transfer processes in donor-bridge-acceptor systems
Autor/es:
BRYAN M. WONG; MARÍA BELÉN OVIEDO
Reunión:
Congreso; 251st American Chemical Society National Meeting & Exposition; 2016
Resumen:
One of the major challenges in science and technology is the efficient conversion of solar energy into readily usable forms. In particular, the enormous size and time scales in solar energy harvesting requires the convergence of multiple scientific disciplines to both improve and optimize these photoconversion processes [1]. Quantum-based simulations play a crucial role in this area since they provide accurate predictions of optical properties of new complex materials. Although very accurate methods exist for predicting optical absorption spectra such as linear-response time-dependent density functional theory [2] or other wave-function based methods, these methods are computationally expensive and can only be applied to relatively small molecules. Consequently, large systems relevant to realistic experiments (such as self-assembled nanostructures and nanomaterials) pose a serious challenge since they lie outside the computational capabilities of these conventional methods.To this end, we have developed a new real-time, time-dependent density functional tight binding (RT-TDDFTB) [3] approach to probe the electron dynamics of donor-bridge-acceptor complexes. Our approach significantly differs from previous linear-response TD-DFT methods in that we directly propagate the one-electron density matrix in the presence of a non-perturbative external field. Furthermore, this RT-TDDFTB approach permits the calculation of large systems composed of thousands of atoms, enabling new quantum simulations that are beyond the reach of traditional Kohn-Sham approaches in conventional TDDFT. We have recently used this method to described the photoinduced charge-transfer processes in light-harvesting systems within a fully quantum dynamic framework. In this work, we show that the charge-transfer state can be modulated by the molecular configuration of the bridge subunit. Most importantly we demonstrate that real-time charge-transfer processes are enhanced and can be controlled by the molecular architecture of this subunit.