Quasiclassical trajectories

Quasiclassical Trajectory Calculations on a H -I- D2 Reaction at 2.20 eV in. The Extended Bom-Oppenheimer Approximation... 

Quasiclassical trajectory calculations are the method of choice for determining the dynamics of intramolecular vibrational energy redistribution leading to a chemical reaction. If this information is desired, an accurate reaction rate can be obtained at little extra expense. 

This means that there is a cross-over temperature defined by (1.7) at which tunneling switches off , because the quasiclassical trajectories that give the extremum to the integrand in (2.1) cease to exist. This change in the character of the semiclassical motion is universal for barriers of arbitrary shape. 

Quantum mechanical effects—tunneling and interference, resonances, and electronic nonadiabaticity— play important roles in many chemical reactions. Rigorous quantum dynamics studies, that is, numerically accurate solutions of either the time-independent or time-dependent Schrodinger equations, provide the most correct and detailed description of a chemical reaction. While hmited to relatively small numbers of atoms by the standards of ordinary chemistry, numerically accurate quantum dynamics provides not only detailed insight into the nature of specific reactions, but benchmark results on which to base more approximate approaches, such as transition state theory and quasiclassical trajectories, which can be applied to larger systems. 

The conclusion that highly vibrationally excited H2 correlated with low-7 CO represents a new mechanistic pathway, and the elucidation of that pathway, is greatly facilitated by comparison with quasiclassical trajectory calculations of Bowman and co-workers [8, 53] performed on a PES fit to high level electronic structure calculations [54]. The correlated H2 / CO state distributions from these trajectories, shown as the dashed lines in Fig. 8, show reasonably good agreement with the data. Analysis of the trajectories confirms that the H2(v = 0—4) population represents dissociation over the skewed transition state, as expected. 

LSTH potential energy parameters non-adiabatic coupling, quasiclassical trajectory (QCT) calculation ... 

H + D2 reaction, quasiclassical trajectory calculation, 167-168 minimal diabatic potential matrix, noninteracting conical intersections, 81-89... 

Y. C. Han, B. C. Shepler, J. M. Bowman. Quasiclassical trajectory calculations of the dissociation dynamics of CH(3)CHO at high energy yield many products, /. Phys. Chem. Lett., 2 1715-1719 (2011). 

The ion-neutral reaction that has received the greatest attention from a theoretical viewpoint is the H2+ -He process. This is because of the relative simplicity of this reaction (a three-electron system), which facilitates accurate theoretical calculations and also to the fact that a wealth of accurate experimental data has been obtained for this interaction. Several different theoretical approaches have been applied to the H2+He reaction, as indicated by the summary presented in Table VI. Most of these have treated the particle-transfer channel only, and few have considered the CID channel. Various theoretical methods applicable to ion-neutral interactions are discussed in the following sections. For the HeH2+ system, calculations using quasiclassical trajectory methods, employing an ab initio potential surface, have been shown to yield results that are in good agreement with the experimental results. 

Quasiclassical trajectory Calculations of opacity functions and cross ... 

Quasiclassical trajectory Dramatic increase of a with vibration at a ... 

Quasiclassical trajectory Calculations on a spline-fitted ab initio surface 459... 

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