1,721,061 research outputs found
Time-dependent calculations on systems of chemical interest: Dynamical and kinetic approaches
Full text linkQuantum mechanical study of the correlation of attack and recoil angles for the Cl + H2 reaction using the stereodirected and discrete variable representations on two potential energy surfaces
No full textThe zero total angular momentum (J = 0) S matrix elements, calculated using a time-dependent wave packet method for the Cl (2P) + H2 reaction on two different potential energy surfaces, have been matrix transformed to the stereodirected and Gauss-Legendre discrete variable representations. Although the results in the two representations are (as expected) quantitatively different with respect to the angular selectivity and-specificity of the reactive process, the qualitative similarity has allowed us to draw for the first time conclusions with respect to some characteristics of the potential energy surface
An innovative computational comparison of exact and centrifugal sudden quantum properties of the N + N-2 reaction
No full textOn a Coupled System of Shallow Water Equations Admitting Travelling Wave Solutions
Full text linkWe consider three inviscid, incompressible, irrotational fluids that are contained between the rigid walls y = −h and y = h +H
and that are separated by two free interfaces. A generalized nonlocal spectral (NSP) formulation is developed, from which
asymptotic reductions of stratified fluids are obtained, including coupled nonlinear generalized Boussinesq equations and (1 + 1)-dimensional shallow water equations. A numerical investigation of the (1 + 1)-dimensional case shows the existence of solitary
wave solutions which have been investigated for different values of the characteristic parameters
Dimerization of methanimine and implications for the aerosols formation in the upper atmosphere of Titan
No full textA detailed comparison of centrifugal sudden and J-shift estimates of the reactive properties of the N + N-2 reaction
No full textAn extended comparison of the reactive properties of the N + N-2 exchange reaction calculated on a non-collinear dominant potential energy surface using both a centrifugal sudden and a J-shift quantum method is reported. The choice of carrying out such an investigation for N + N-2 is motivated by the fact that the best available (and currently used for spacecraft re-entry simulations) computed set of kinetic data has been worked out using the low level J-shift approximation though based on exact quantum zero total angular momentum probabilities. The fact that our investigation is carried out for a heavy system and a potential energy surface free of wells in the strong interaction region minimizes the occurrence of tunnel, resonance and interference effects which would make the rationalization of the result difficult and the centrifugal sudden treatment less accurate. The study has provided evidence of two important limits of the J-shift approximation: the wrong determination of the maximum value of the total angular momentum quantum number J contributing to reactivity and the lack of deformation of the partial reactive probability dependence on energy at fixed J value. Accordingly, it has been found that the J-shift state-specific cross sections underestimate the corresponding CS values when the initial diatomic rotational energy is low while the situation reverses when the initial diatomic rotational energy is high
The shape of the potential energy surface and the thermal rate coefficients of the n + N2 reaction
No full textFull-dimensional quantum time-dependent calculations of the detailed probabilities of the N + N2 reaction have been performed on different potential energy surfaces, initial quantum states, and total angular momentum quantum numbers. The calculations allowed a rationalization of the effect of both moving the saddle to reaction out of collinearity and lowering its height. On some of these surfaces, more extended studies of the reactive dynamics of the system were performed. On one of them also, thermal rate coefficients were computed using J = 0 quantum probabilities and the J-shift model after testing the applicability of such a model against centrifugal sudden results. A comparison of the calculated thermal rate coefficients with theoretical and experimental data available from the literature is also made, and possible effects of inserting an intermediate well at the top of the saddle are argued
Theoretical study of formation routes and dimerization of methanimine: implications for the aerosols formation in the upper atmosphere of Titan
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