| Sažetak: | Three-dimensional calculations on the vibrationally excited exchange reactions D + BrH(v = 1) → DBr(v′) - H and H - BrH(v = 1) → HBr(v′) + H are reported. Two quantal sudden techniques are used to calculate vibration-rotation, integral and differential cross sections, and rate coefficients. In the first (ESA CSA) method, the energy and centrifugal sudden approximations are applied to the entrance and exit channel hamiltonians respectively. The second, less accurate, technique is the infinite-order-sudden approximation (IOSA). A diatomics-in-molecules potential energy surface is used which has been optimised to reproduce the experimental rate coefficient for the D + BrH(v = 0) - DBr + H reaction. The IOSA and ESA CSA results are in good agreement. It is found that the v = 1 → v′ = 0 reactions have quite large rate coefficients. New calculations are also reported for the D(H) + BrH(v = 0) exchange reactions. For the v = 0 reaction, it is found that the H-atom rate coefficients are larger than those for the D-atom reaction due to tunnelling, while the reverse is true for the BrH(v = 1) reactions, where tunnelling is less important. The average energy for product translation, and differential cross section, for the D + BrH(v = 0) reaction, obtained in a previous molecular-beam experiment, are in good agreement with our ESA CSA results, computed for similar collisional conditions. © 1983.
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