Ultrafast structural dynamics of UV photoexcited <i>cis</i>,<i>cis</i>-1,3-cyclooctadiene observed with time-resolved electron diffraction
Sri Bhavya Muvva, Yusong Liu, Pratip Chakraborty, J. Pedro F. Nunes, Andrew Attar, Surjendu Bhattacharyya, Kurtis Borne, Elio G. Champenois, Nathan Goff, Kareem Hegazy, Matthias C. Hoffmann, Fuhao Ji, Ming‐Fu Lin, Duan Luo, Lingyu Ma, Asami Odate, Shashank Pathak, Daniel Rolles, Artem Rudenko, Sajib Kumar Saha, Xiaozhe Shen, Xijie Wang, Matthew R. Ware, Stephen Weathersby, Peter M Weber, Kyle Wilkin, Thomas Wolf, Yanwei Xiong, Xuan Xu, Jie Yang, Spiridoula Matsika, Thomas Weinacht, Martin Centurion
Abstract
-1,3-cyclooctadiene, a large-flexible cyclic conjugated diene molecule, upon excitation with 200 nm using mega-electron-volt ultrafast electron diffraction and trajectory surface hopping dynamics simulations. We tracked the photoinduced structural changes from the Franck-Condon region through the conical intersection seam to the ground state. Our findings revealed a novel primary reaction coordinate involving ring distortion, where the ring stretches along one axis and compresses along the perpendicular axis. The nuclear wavepacket remains compact along this reaction coordinate until it reaches the conical intersection seam, and it rapidly spreads as it approaches the ground state, where multiple products are formed.