We have investigated the photodynamics of β-D-glucose employing our field-induced surface hopping method (FISH), which allows us to simulate the coupled electron-nuclear dynamics, including explicitly nonadiabatic effects and light-induced excitation. Our results reveal that from the initially populated S1 and S2 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, while 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 reveals 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 S1 state through the same types of CIs as observed in the field-free simulations.
@article{arxiv.1803.06856,
title = {Ultrafast Photodynamics of Glucose},
author = {Jens Petersen and Joachim O. Lindner and Roland Mitric},
journal= {arXiv preprint arXiv:1803.06856},
year = {2018}
}