Optical Cavity Manipulation and Nonlinear UV Molecular Spectroscopy of Conical Intersections in Pyrazine

Optical cavities provide a versatile platform for manipulating the excited-state dynamics of molecules via strong light-matter coupling. We employ optical absorption and two-multidimensional electronic spectroscopy simulations to investigate the effect of optical cavity coupling in the nonadiabatic dynamics of photoexcited pyrazine. We observe the emergence of a novel polaritonic conical intersection (PCI) between the electronic dark state and photonic surfaces as the cavity frequency is tuned. The PCI could significantly change the nonadiabatic dynamics of pyrazine by doubling the decay rate constant of the S₂state population. Moreover, the absorption spectrum and excited-state dynamics could be systematically manipulated by tuning the strong light-matter interaction, e.g., the cavity frequency and cavity coupling strength. We propose that a tunable optical cavity-molecule system may provide promising approaches for manipulating the photophysical properties of molecules.