ISOTOPE EFFECTS ON THE RATE CONSTANTS FOR THE PROCESSES O-2-]O+O-2 AND O-2+O+AR-]O-3+AR - ON A MODIFIED GROUND-STATE POTENTIAL-ENERGY SURFACE FOR OZONE(O)

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 ca lculated at 300 K for various isotopic oxygen atoms on a modified mode l potential energy surface (PES). The dynamics for both of the process es has been simulated using quasiclassical trajectories and importance sampling methods. Due to experience from previously performed calcula tions on the systems, we have modified the ground-state PES for ozone obtained by Yamashita et al. (YMQL). To describe the Ar-(O-3) potentia l we used a pairwise additive potential for the Ar-O interaction from Ar-glyoxal. (C) 1997 Elsevier Science B.V.