Theoretical modeling of coherent proton transfer dynamics and pump probe spectroscopy simulation

Proton transfer reaction is ubiquitous in chemistry and biology. Pump probe spectroscopy shows general feature of fast rising and oscillation signal of excited state proton transfer which can only be explained by quantum mechanics. However, due to the interplay of electron rearrangement, nuclear vibrations, skeletal torsion and molecule-solution interaction, it's difficult to use ab-initial quantum dynamics calculation to illustrate pump probe signal. Here, we adopt the a vibronic coupling Hamiltonian and used methods of open quantum dynamics to simulate pump probe signal of HBT(2-(2′-Hydroxyphenyl)benzothiazole) and compare with experiment. Our method will make a brige between experiment and ab-intial calculation, and also provide a framework to describe a chemical reaction in a wave function(density matrix) perspective. Furthermore, because of the quantum mechanical nature of excited state proton transfer, it's possible to realize a superposition of two pathways for a dimer molecule with two proton transfer sites, which brings a new mechanism for general chemical reaction. Using similar model Hamiltonian, we found for isolated dynamics, a superposition reaction shows interference pattern of nulcear density while single proton transfer does not.