Mixed quantum-classical simulation of molecules in a cavity

Photons in an optical cavity can strongly interact with electronic and vibronic state of molecules, which provides great promise to manipulate chemical reaction in cavity. Mixed quantum-classical methods, such as mean-field Ehrenfest, have been successfully applied to traditional photochemical reaction and provide many valuable insights into the reaction mechanisms. In this talk, we will present our recent results on how to generalize the mean-field Ehrenfest dynamics to the molecules in cavity by treating nuclei classically and other degrees of freedom quantum mechanically. The derived quantum force is general and can be used to include any number of electronic and photon states. As an example, we use our method to study the dissociation of LiF in cavity and compare the results with exact quantum simulation, which shows the reaction outcomes can be controlled by the coupling strength and the dipole self-energy term. Our approximate approach produces accurate results compared with exact quantum simulation, and can be broadly applied to investigate molecular reactions in the cavity.