Mondelo-Martell Manel, Brey Dominik, Burghardt Irene
Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt am Main, Germany.
J Chem Phys. 2022 Sep 7;157(9):094108. doi: 10.1063/5.0104729.
We report on quantum dynamical simulations of inter-chain exciton transport in a model of regioregular poly(3-hexylthiophene), rr-P3HT, at finite temperature using the Multi-Layer Multi-Configuration Time-Dependent Hartree method for a system of up to 63 electronic states and 180 vibrational modes. A Frenkel Hamiltonian of HJ aggregate type is used along with a reduced H-aggregate representation; electron-phonon coupling includes local high-frequency modes as well as anharmonic intermolecular modes. The latter are operative in mediating inter-chain transport by a mechanism of transient localization type. Strikingly, this mechanism is found to be of quantum coherent character and involves non-adiabatic effects. Using periodic boundary conditions, a normal diffusion regime is identified from the exciton mean-squared displacement, apart from early-time transients. Diffusion coefficients are found to be of the order of 3 × 10 cm/s, showing a non-linear increase with temperature.
我们报告了在有限温度下，使用多层多组态含时哈特里方法对多达63个电子态和180个振动模式的体系，对区域规整聚（3 - 己基噻吩）（rr - P3HT）模型中的链间激子输运进行的量子动力学模拟。使用了HJ聚集体类型的弗伦克尔哈密顿量以及简化的H - 聚集体表示；电子 - 声子耦合包括局域高频模式以及非谐分子间模式。后者通过瞬态局域化类型的机制介导链间输运。引人注目的是，发现该机制具有量子相干特性且涉及非绝热效应。使用周期性边界条件，除了早期瞬态外，从激子均方位移确定了正常扩散区域。发现扩散系数约为3×10 厘米/秒，随温度呈非线性增加。
