Quantum mechanical and quasi-classical trajectory reaction probabilities and cross sections for the S(¹D) + H₂,D₂,HD insertion reactions

Abstract

Time-independent quantum mechanical (QM) and quasi-classical trajectory (QCT) calculations of reaction probabilities at total angular momentum J = 0 as a function of collision energy for the S(1D) + H2(v = 0, j = 0), S(1D) + D2(v = 0, j = 0) and S(1D) + HD(v = 0, j = 0) reactions have been performed on a recent ab initio potential energy surface. In addition, QCT calculations of integral cross sections as a function of collision energy (the excitation functions) have been carried out for the same reactions. The QCT excitation functions and those obtained by applying a capture model to the QM reaction probabilities are compared with the available experimental determinations. The QCT and QM methods reproduce the shape of the measured excitation functions quite satisfactorily. However, the theoretical intramolecular and intermolecular isotope effects are in disagreement with those obtained experimentally.

Cold and ultracold dynamics of the barrierless D+ + H2 reaction: Quantum reactive calculations for ∼R−4 long range interaction potentials

“…[87][88][89][90] In this method, the configuration space is divided into inner and outer regions by the definition of a matching hyper-radius, ρ 0 , beyond which no inelastic or reactive transition may appreciably occur. The positions of the nuclei in the inner region are described in terms of Smith-Witten hyperspherical democratic coordinates.…”

Extraction of state-to-state reactive scattering attributes from wave packet in reactant Jacobi coordinates

“…These results have served as accurate benchmarks for dynamical studies of complex-forming reactions, featuring barrierless reaction pathways through deep potential wells. [5][6][7][8][9] However, due to the N 3 ͑N is the number of basis functions͒ scaling law in the formalism, it is extremely difficult to extend the TID-CC method to calculate cross sections for more complex systems, such the H + O 2 reaction, which possesses a deep well and two heavy ͑nonhydrogen͒ atoms. 10 On the other hand, the TDWP method scales more favorably than the TID-CC method in both memory and the number of arithmetic operations because the basic operation involves matrix-vector multiplication.…”

Dynamics of theS(D21)+HD(j=0Lara1, Chefdeville2, Hickson3 et al. 2012Phys. Rev. Lett.403290View full textAdd to dashboardCite

“…Although the theoretical branching ratio ðDS þ HÞ= ðHS þ DÞ ¼ 1:72 at E T ¼ 13:8 meV is only slightly higher than the upper error limit of the experimental one, variations in both theoretical and experimental values are uncorrelated throughout the whole collision energy range. The branching ratio has been the subject of much debate in previous experimental and theoretical papers treating Sð 1 D 2 Þ þ HD reaction dynamics [17,19,[22][23][24][25] while our own experimental values, which attain 1.17 on average between E T ¼ 31-54:2 meV, are noticeably different from the previous crossed-beam determination ðDS þ HÞ= ðHS þ DÞ ¼ 0:72 AE 0:07 between E T ¼ 31 to 570 meV [17]. The present calculations are unable to reproduce the three peaks observed in the experimental HS þ D channel.…”