Nonadiabatic dynamics study of bridged-azobenzene by the time-dependent density functional tight-binding method

Time-dependent density functional tight-binding (TD-DFTB) method is a fast electronic structure method for excited states properties of large systems with the accuracy close to pure TDDFT method. In this paper, we use the TD-DFTB method to study nonadiabatic molecular dynamics of large systems where the Zhu-Nakamura theory is used to estimate the probabilities of nonadiabatic transition between the excited and ground states in the surface hopping procedure. To show the applicability of the method to complex molecular systems, on-the-fly nonadiabatic dynamics calculations combined with the TD-DFTB method are implemented in the mechanism study of ethylene-bridged azobenzene photoisomerization. The results show that the nonadiabatic dynamics can obtain a reasonable result of the whole isomerization process, which are consistent with other theoretical results and the experimental observation. The result also demonstrates that TD-DFTB nonadiabatic dynamics is an efficient tool for the exploration of the photo dynamics in large scale molecular systems.