Journal of Physical Chemistry A, Vol.102, No.11, 1912-1917, 1998
Role of Renner Teller and spin-orbit interaction in the dynamics of the O(P-3)+CH2ICl reaction
Reactive scattering of O(P-3) atoms with CH2ICl molecules has been measured at initial translational energies E similar to 46 and 17 kJ mol(-1) using a supersonic beam of O atoms seeded in He and Ne buffer gases generated from a high-pressure microwave discharge source. At the higher initial translational energy, the IO product scattering can be resolved into two components; one showing forward and backward peaking with a product translational energy distribution peaking at low energy with a tail extending out to higher energy, and the other that peaks in the backward direction with higher product translational energy. At lower initial translational. energy, the IO product scattering does not allow the resolution of two components but peaks in the backward direction with a higher product translational energy than for scattering in the forward hemisphere. The slow component is attributed to dissociation of a long-lived OICH2Cl complex formed by intersystem crossing from the initial triplet (3)A " potential energy surface to the underlying singlet (1)A' potential energy surface, The fast component is attributed to direct reaction over the tripler potential energy surface with the sharp backward peaking arising from reaction on the (3) Pi(2) and (3) Pi(1) spin multiplet surfaces in near collinear OICH2Cl configurations and the scattering in the sideways and forward directions arising from reaction on the (3)A " Renner Teller surface in strongly bent configurations. The contribution of the slow component is approximately one-third that of the fast component to the total reaction cross section for IO product scattering.