Role of cooperative network interaction in transition region of roaming reactions: Non-equilibrium steady state vs. thermal equilibrium reaction scheme

摘要

This paper proposes a new type of roaming mechanism. We find a signature of trajectory with chaotic behavior in the action-angle diagram of the H + H_2 reaction on a LEP surface, namely the trajectory is found to be very sensitive to the initial angle variable which corresponds to the phase of the H_2 vibration. The trajectory pattern switches from the direct to the complex forming mechanism, and vice versa, in the angle range (0 ～ π). In the complex forming angle range, trajectories switch from reactive to non-reactive randomly and suddenly, as the result, we cannot predict the collision pattern from the initial conditions. Therefore, we may classify such trajectory as a new type of roaming with chaotic behavior, and it is different from the ordinary trajectory with deterministic behavior. This chaotic behavior could be due cooperative nearby network interaction (CNN effect). We also suggest that the KPP (Kolmogorow-Petrovsky-Piskounov) equation is useful to estimate the density gradient of the activated reagents, so that one can evaluate the branching ratio to various exit channels, such as triple fragmentation, tight transition state, or the roaming channel with the aid of the present classical trajectory calculation.