A comparative study of quantum mechanical and classical trajectory calculations for an A + BC collinear non-adiabatic collision

Abstract

State-to-state transition probabilities have been calculated for collinear collisions of the type

for a range of collision energies and small and large values of a non-adiabatic coupling parameter. Comparison has been made between the results of quantum mechanical coupled channel calculations, and two trajectory based models; a surface hopping and a modified classical path model. The quantum mechanical charge transfer probabilities show oscillations in the energy spectrum which we attribute to resonances in the reactant channel. Oscillations are also shown in the classical path calculations. The surface hopping charge transfer probabilities vary smoothly with collision energy, and at low energies the transition probabilities are much higher than the quantum mechanical results, particularly for low values of the non-adiabatic coupling parameter. The relative state-to-state transition probabilities (0-v′/0-0) are overestimated by both trajectory models; the Franck-Condon factors, in contrast, underestimate these factors. For v′ ⩾ 2 the classical path ratios are much better than either the surface hopping or Franck-Condon values.

Additional information

Notes on contributors

L.J. Dunne

Visiting research fellow at the University of Sussex.