The simulations presented above give an upper limit of the free-energy barrier change when a possible EF of water microdroplet is perfectly aligned along the reaction coordinate of a given chemical reaction. However, microdroplet interfaces are strongly dynamic entities, making rapidly fluctuating the orientation and magnitude of the IEF, thus affecting its putative catalytic properties. To shed light on this aspect of pivotal concern, we performed unbiased AIMD simulations (i.e., no MetD) to evaluate the genuine distribution of the IEF at the air-water interface by computing the IEF generated by interfacial water molecules along the z-axis of the DA reaction. To do so, we constructed an air-water interface model with 200 water molecules and placed the RC at the interface (Figure ). The system was simulated for 50 ps, during which the RC was kept fixed while the water molecules were allowed to evolve dynamically by first principles at finite temperature.