https://www.selleckchem.com/products/shp099-dihydrochloride.html Non-adiabatic molecular dynamics of neutral chrysene and tetracene molecules is investigated using Tully's fewest switches surface hopping algorithm coupled to the time-dependent density functional based tight-binding (TD-DFTB) method for electronic structure calculations. We first assess the performance of two DFTB parameter sets based on the computed TD-DFTB absorption spectra. The main focus is given to the analysis of the electronic relaxation from the brightest excited state following absorption of a UV photon. We determine the dynamical relaxation times and discuss the underlying mechanisms. Our results show that the electronic population of the brightest excited singlet state in armchair-edge chrysene decays an order-of-magnitude faster than the one in zigzag-edge tetracene. This is correlated with a qualitatively similar difference of energy gaps between the brightest state and the state lying just below in energy, which is also consistent with our previous study on polyacenes.There is strong interest in understanding the behavior of water in its supercooled state. While many of the qualitative trends of water dynamical properties in the supercooled regime are well understood, the connections between the structure and dynamics of room temperature and supercooled water have not been fully elucidated. Here, we show that the reorientational time scales and diffusion coefficients of supercooled water can be predicted from simulations of room temperature liquid water. Specifically, the derivatives of these dynamical time scales with respect to inverse temperature are directly calculated using the fluctuation theory applied to dynamics. These derivatives are used to predict the time scales and activation energies in the supercooled regime based on the temperature dependence in one of two forms that based on the stability limit conjecture or assuming an equilibrium associated with a liquid-liquid phas