Browsing by Subject "potential-energy surfaces"

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    Extraction of state-to-state reactive scattering attributes from wave packet in reactant Jacobi coordinates
    (2010) Sun, Zhigang; Guo, Hua; Zhang, Dong H
    The S-matrix for a scattering system provides the most detailed information about the dynamics. In this work, we discuss the calculation of S-matrix elements for the A+BC -> AB+C, AC+B type reaction. Two methods for extracting S-matrix elements from a single wave packet in reactant Jacobi coordinates are reviewed and compared. Both methods are capable of extracting the state-to-state attributes for both product channels from a single wave packet propagation. It is shown through the examples of H+HD, Cl+H-2, and H+HCl reactions that such reactant coordinate based methods are easy to implement, numerically efficient, and accurate. Additional efficiency can be gained by the use of a L-shaped grid with two-dimensional fast Fourier transform. (C) 2010 American Institute of Physics. [doi:10.1063/1.3328109]
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    Time-dependent wavepacket investigation of state-to-state reactive scattering of Cl with para-H-2 including the open-shell character of the Cl atom
    (2010) Sun, Z; Zhang, DH; Alexander, MH
    We describe a time-dependent wavepacket based method for the calculation of the state-to-state cross sections for the Cl+H-2 reaction including all couplings arising from the nonzero spin and electronic orbital angular momenta of the Cl atom. Reactant-product decoupling allows us to use a physically correct basis in both the reactant and the product arrangements. Our calculated results agree well with the experimental results of Yang and co-workers. We also describe a model with two coupled potential energy surfaces, which includes the spin-orbit coupling, which is responsible for the largest non-Born-Oppenheimer effects in the Cl+H-2 reaction but neglects the off-diagonal electronically diabatic coupling and all Coriolis couplings due to the electronic spin and orbital angular momenta. The comparison of the results of the full six-state and two-state models with an electronically adiabatic (one-state) description reveals that the latter describes well the reaction out of the ground spin-orbit state, while the two-state model, which is computationally much faster than the full six-state model, describes well the reaction from both the ground and excited spin-orbit states.