26 research outputs found

    Approximate Quantum Mechanical Cross Sections and Rate Constants for the H + O3 Atmospheric Reaction Using Novel Elastic Optimum Angle Adiabatic Approaches

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    Three-dimensional quantum dynamics computations of cross sections and rate constants for the atmospheric reaction H + O3 → O2 + OH are presented. Using a novel elastic optimum angle adiabatic approach published in a previous paper (Varandas, A. J. C.; Szichman, H. Chem. Phys. Lett. 1998, 295, 113), the calculated cross sections cover the range of translational energies 0.035 ≤ Etr/eV ≤ 0.300. Applications of the new approach using both single-path and multiple-path schemes are reported. The results are compared with available classical trajectory and infinite-order-sudden-approximation results. It may be concluded that the calculations obtained from the single-path model give an improved agreement with respect to the sudden ones when compared with the classical trajectory results. In turn, the quantum elastic optimum angle adiabatic multiple-path results show excellent agreement with the same classical results

    How double layers accelerate charged particles

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    After the theory of dynamic double layers in laser-produced plasmas arrived at several significant results in agreement with measurement, including particle acceleration, a clarification was given to the paper by Bryant et al. (1992) negating such acceleration. The discrepancy seems to be in the definition of static double layers in contradiction with dynamic double layers that are created in laser-induced plasma. We present here new results on the acceleration of electrons in a laser-irradiated plasma by double layer mechanisms. A simple analytical example is give

    A three-dimensional quantum mechanical study of the atmospheric reaction: infinite-order sudden approximation and novel adiabatic approaches vs. quasiclassical trajectories

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    We present a quantum mechanical, three-dimensional infinite-order-sudden-approximation study of the reaction using a recently reported double many-body expansion potential energy surface. The reaction is treated as coplanar, for which a 3D treatment represents still a reduced dimensionality analysis. The results are compared with experimental data and previously reported quasiclassical trajectory calculations which employed the same potential. Novel adiabatic approaches have also been developed. In comparison with the trajectory calculations and experiment, the agreement of the adiabatic results is good. Striking deficiencies are noted for the sudden approximation near the reaction threshold.http://www.sciencedirect.com/science/article/B6TFN-3TX55BV-K/1/120aaa74386663e3ee89839b72bc7e8

    New results in the decay of 150^{150}Ho and 150^{150}Tm

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    New results in the decay of 150^{150}Ho and 150^{150}Tm

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    Quantum Dynamical Rate Constant for the H + O3 Reaction Using a Six-Dimensional Double Many-Body Expansion Potential Energy Surface

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    We present a quantum mechanical, three-dimensional, infinite-orden-sudden-approximation study of the H + O3 atmospheric reaction using a recently reported double many-body expansion potential energy surface for ground-state HO3. The results are compared with existing experimental data and previously reported quasiclassical trajectory calculations which employed the same interaction potential. Agreement with the recommended experimental data is moderate, but encouraging when compared with the data of Clyne and Monkhouse, which extends over the range of temperatures 300 ≤ T/K ≤ 650, and with the recent measurement of Greenblatt and Wiesenfeld for T = 300 K. In comparison with the classical trajectory results, the agreement is also moderate, the differences being attributed to both methodological approximations in the quantum formalism and the problem of zero-point energy leakage in classical dynamics

    Quantum Dynamical Rate Constant for the H + O 3

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