Quantum and Quasi-Classical Studies of the O(3P) + HCl yields OH + Cl(2P) Reaction Using Benchmark Potential Surfaces (PREPRINT)

摘要

We have performed quantum mechanical (QM) dynamics calculations within the independent-state approximation with new benchmark triplet A' and A's; surfaces B. Ramachandran et al. J. Chem. Phys. 119, 9590 (2003). for the ro-vibronic state-to-state measurements of the reaction O(3P) + HCl(v=2, j=1,6,9) 'No. 61614; OH(v j ) + Cl(2P) Zhang et al. J. Chem. Phys. 94, 2704 (1991). The QM and experimental rotational distributions peak at similar OH(j) levels, but the QM distributions are significantly narrower than the measurements and previous quasi-classical dynamics studies. The OH(low j) populations observed in the measurements are nearly absent in the QM results. We have also performed quasi-classical trajectory with histogram binning (QCT- HB) calculations on these same benchmark surfaces. The QCT-HB rotational distributions, which are qualitatively consistent with measurements and classical dynamics studies using other surfaces, are much broader than the QM results. Application of a Gaussian binning correction (QCT-GB) dramatically narrows and shifts the QCT-HB rotational distributions to be in very good agreement with the QM results. The large QCT-GB correction stems from the special shape of the joint distribution of the classical rotational/vibrational action of OH products. We have also performed QM and QCT calculations for the transition, O + HCl(v=0,T=300 K) & No. 61614; OH(v j ) + Cl from threshold to '130 kcal mol-1 collision energy as a guide for possible future hyperthermal O- atom measurements. We find in general a mixed energy release into translation and rotation consistent with a late barrier to reaction. Angular distributions at high collision energy are forward peaked, consistent with a stripping mechanism. Direct collisional excitation channel cross sections, O + HCl(v=0, T=300) & No. 61614; O + HCl(v =1), in the same energy range are large, comparable in.