of the initial states above, in Fig. we show the quantum average system energy ⟨H S ⟩ and photon number ⟨n c ⟩ for the three states of interest at ω c = 1182 cm -1 -the region in Fig. (a) where significantly different cavityinduced modulation of ⟨P iso ⟩ are observed. For the initial wavepacket with q i = -0.9 au it is clear that initially the system loses energy to the cavity, which is mirrored in Fig. ) as an increase in the average number of photons. Consequently, as pointed out by Fischer et al , the coherent exchange of energy between the cavity and the reactive mode leads to a suppression of the isomerization probability. On the other hand, for the other two cases corresponding to q i = -0.602 au and q i = -0.439 au, the cavity initially transfers energy to the system and hence, based on the line of reasoning above, leads to enhanced isomerization. However, note that in all three cases system energy oscillates over the entire time period and hence the time averaged system energy ⟨H S ⟩ needs to be considered. Figure (a) clearly shows that for q i = -0.9 au ⟨H S ⟩ is nearly the same as the uncoupled value ⟨H S ⟩(η = 0), whereas for the other two cases ⟨H S ⟩ > ⟨H S ⟩(η = 0). Therefore, for q i = -0.602 and -0.439 au there is an effective cavity to system energy transfer which leads to enhanced isomerization.