Institut für physikalische und theoretische Chemie, Julius-Maximilians-Universität Würzburg , Emil-Fischer-Str. 42, 97074 Würzburg, Germany.
J Phys Chem B. 2018 Jan 11;122(1):19-27. doi: 10.1021/acs.jpcb.7b08602. Epub 2017 Dec 20.
We have investigated the photodynamics of β-d-glucose employing our field-induced surface-hopping (FISH) method, which allows us to simulate the coupled electron-nuclear dynamics, explicitly including nonadiabatic effects and light-induced excitation. Our results reveal that from the initially populated S and S states, glucose returns nonradiatively to the ground state within about 200 fs. This takes place mainly via conical intersections (CIs), whose geometries in most cases involve the elongation of a single O-H bond, whereas in some instances, ring-opening due to dissociation of a C-O bond is observed. Experimentally, excitation to a distinct excited electronic state is improbable due to the presence of a dense manifold of states bearing similar oscillator strengths. Our FISH simulations, explicitly including a UV laser pulse of 6.43 eV photon energy, reveal that after initial excitation, the population is almost equally spread over several close-lying electronic states. This is followed by a fast nonradiative decay on the time scale of 100-200 fs, with the final return to the ground state proceeding via the S state through the same types of CIs as observed in the field-free simulations.
我们采用场致跃迁（FISH）方法研究了β-D-葡萄糖的光动力学，该方法允许我们模拟耦合的电子-核动力学，明确包括非绝热效应和光激发。我们的结果表明，从最初占据的 S 和 S 态，葡萄糖在大约 200 fs 内非辐射地返回基态。这主要通过锥形交叉（CI）发生，其几何形状在大多数情况下涉及单个 O-H 键的伸长，而在某些情况下，观察到由于 C-O 键的解离而导致的开环。实验上，由于存在具有相似振子强度的密集状态简并，激发到独特的激发电子态是不可能的。我们的 FISH 模拟，明确包括 6.43 eV 光子能量的紫外激光脉冲，表明初始激发后，种群几乎均匀分布在几个接近的电子态上。随后，在 100-200 fs 的时间尺度上快速非辐射衰减，最终通过 S 态通过与无场模拟中观察到的相同类型的 CI 返回基态。
