Time-dependent quantum mechanical calculations on H+O2 for total angular momentum J>0

Abstract

The H+O2→OH+O reaction has been studied with a time-dependent wave packet method for total angular momentum J=0, 1, 2, and 5, using the Coriolis coupled method [E. M. Goldfield and S. K. Gray, Comp. Phys. Commun. 98, 1 (1996)] on parallel computers. We find that at higher energies the total reaction probability decreases by a factor of 2 in going from a J=0 calculation to a J=1 calculation. The effect for higher J with respect to J=1 is less dramatic. We investigated the decrease in reaction probability for J>0 by examining the different initial conditions with respect to Ω, the projection of J onto the body-fixed z axis for the J>0 calculations. We conclude that the reaction probability is a strong function of Ω. If Ω=0 for J>0, collision geometries are accessible that lead to an enhanced reaction probability.

Efficient time-independent wave packet scattering calculations within a Lanczos subspace: H+O2 (J=0) state-to-state reaction probabilities

“…Only a limited number of rigorous quantum calculations have been so far performed for the total reaction probabilities. While our total reaction probabilities are qualitatively similar to previous calculations 45,48,50 ͑e.g., the total reaction probabilities increase rapidly from about 1.25 eV͒, the fine structure is different, as indeed it differs between the cited references. It should be mentioned that Meijer and FIG.…”

“…2 in this article͒. As Meijer and Goldfield 50 have pointed out, for the HϩO 2 system the computed resonance structure and hence the profile of reaction probabilities as a function of energy will be sensitive to many details of the calculations ͑DVR grid spacings, method of imposing absorbing boundary conditions, etc.͒. This notwithstanding, one does expect that the overall profile and any prominent features will agree among different computational methods.…”

“…͑b͒ The same as ͑a͒, but for product OH states ( ϭ1,j) with jϭ0. Goldfield 50 have also calculated the total probabilities for J Ͼ0, but without final state resolution. A particular feature of our calculations as revealed in Fig.…”

“…The potential energy surface of HO 2 supports a deep well, 42 making HO 2 a somewhat challenging system. Due to its importance in combustion chemistry and atmospheric chemistry, several groups [43][44][45][46][47][48][49][50][51] have performed rigorous quantum scattering calculations on this system. Most have been focused on initial state selected total reaction probabilities or cumulative reaction probabilities.…”

Unimolecular rovibrational bound and resonance states for large angular momentum: J=20 calculations for HO2

“…The reader is referred to Wolfrum for some detailed comparisons. 29 On the theoretical side, calculations performed on three levels, namely, statistical theory ͑ST͒, classical trajectory ͑CT͒, and quantum mechanics ͑QMs͒, have been reported 11,21,[30][31][32][33][34][35][36][37] ͑not all the references have been listed here͒. The potential-energy surfaces ͑PESs͒ used are those by Melius and Blint, 38 Pastrana et al, 39 Kendrick and T Pack, 40 and Troe and co-workers.…”