Qualitative interpretation of the dynamics of collinear exchange reactions

The many-channel resonance scattering theory is adapted for the purpose of investigation of the dynamics of collinear chemical exchange reactions. A general expression for the scattering matrix is presented which appears to be useful for developing a simple algebraic procedure of calculation of the parameters needed for various resonance expansions. The case of weak nonadabatic coupling between vibrational levels is studied in detail by means of a version of perturbational treatment that is valid for a resonance situation. This approach is then applied to account for the qualitative peculiarities observed in recent experimental and numerical investigations of reactive collosions A + BC → AB + C. The Polanyi rules are formulated in terms of the accessibility of a transition zone region for adiabatic channel functions. Several mechanisms of product population inversion are discussed. That of them occurring at low kinetic energies in the transition zone is supposed to arise due to the resonance scattering caused by the wells of dynamic adjabatic potentials, which have been revealed by Wu, Johnson and Levine. The estimations for Breit-Wigner reduced width amplitudes are given in framework of weak coupling approximation. They are shown to provide a meaningful background for understanding of resonance phenomena found in quantum calculations.