In order to gain a different perspective on these classes of trajectories, in Fig. we show the SOS for ω c = ω R with different choices of the sectioning conditions. From these SOS it is immediately clear that the 1:1 region occupies a major part of the reactant well and the interwell tori are centered around the TS. In Fig. (c) we show typical trajectories corresponding to these features in the configuration space. It is also immediately apparent from Fig. (a) that the initial state with q i = -0.9 au is situated in the 1:1 resonance part of the reactant well. On the other hand, the two other initial states of interest with q i = -0.602 au and -0.439 au are situated in the vicinity of the regular-chaotic border. Therefore, one can see a correlation between the cavity-system dynamics in Fig. and the phase space features for ω c ≈ ω R .