Isotope effects on the rate constants for the processes O-2+O->O+O-2 and O-2+O+Ar->O-3+Ar - On a modified ground-state potential energy surface for ozone

Rate constants for the formation of ozone O-2(X,(3) Sigma(g)(-))+O(P-3)+Ar --> O-3((X) over tilde,(1)A(1))+Ar and the exchange reaction O-2(X,(3) Sigma(g)(-))+O(P-3)+O-2(P-3)+O-2(X,(3) Sigma(g)(-)) have been calculated at 300 K for various isotopic oxygen atoms on a modified model potential energy surface (PES). The dynamics for both of the processes has been simulated using quasiclassical trajectories and importance sampling methods. Due to experience from previously performed calculations on the systems, we have modified the ground-state PES for ozone obtained by Yamashita et al. (YMQL). To describe the Ar-(O-3) potential we used a pairwise additive potential for the Ar-O interaction from Ar-glyoxal. (C) 1997 Elsevier Science B.V.