Energy disposal in the O(3P) plus HCl reaction:: Classical dynamics and comparison to experiment

The energy disposal in the O(P-3)+HCl(v=2, j=1,6,9)--> OH(v',j')+Cl reaction is analyzed using the results of fairly extensive quasiclassical trajectory (QCT) calculations on a realistic potential energy surface for the (3)A state of this system. These results are compared to the experimental observations of Zhang [R. Zhang, W. J. van der Zande, M. J. Bronikowski, and R. N. Zare, J. Chem. Phys. 94, 2704 (1991)]. The experimental and QCT product rotational distributions in the OH (v'=1) manifold, P-1(j'), are shown to be very similar in shape, but not magnitude, to the purely statistical prior distribution. On the other hand, the rotational distributions in the ground vibrational state of OH, P-0(j(')), show significant deviations from prior distributions. A careful examination of several reactive trajectories suggests that (a) a direct abstraction mechanism is responsible populating the v(')=1 states, (b) secondary encounters with R(HCl)less than or equal to R(HCl)double dagger and theta(OHCl)> 100 degrees are responsible for populating the v(')=0, j(')greater than or equal to 11 states, and (c) secondary encounters with R(HCl)greater than or equal to R(HCl)double dagger and theta(OHCl)less than or equal to 100 degrees may be responsible for populating the v(')=0, j(')< 11 states. The last observation raises the speculative but intriguing possibility that the state v'=0, j'=11 may represent a phase space boundary between the two types of secondary encounters. (C) 2000 American Institute of Physics. [S0021-9606(00)01308-8].