The GFSH approach was employed in the nonadiabatic dynamics simulations both inside and outside the cavity in this work. The initial condition is generated from a separate (independent) set of initial nuclear configurations near the ground-state minimum of the cis isomer using the Wigner sampling at T = 0 K. The initial Wigner distribution is sampled from the ground vibrational state ν = 0 on the ground electronic state |g⟩, where the normal mode frequencies (in the harmonic approximation) are calculated based on the approach outlined in Ref. 61,62, as implemented in the JADE-NAMD package. In particular, the nuclear density ρ W ( R, P) in terms of the molecular normal-mode frequencies {ω k } and phase space variables { R, P} is given as