Classical trajectory and statistical adiabatic channel study of the dynamics of capture and unimolecular bond fission. V. Valence interactions between two linear rotors

The combination of two linear rotors forming linear or nonlinear adducts is treated using standardized valence potentials. Classical trajectory (CT) and statistical adiabatic channel (SACM) calculations are used for the calculation of thermal capture rate constants. At very low temperatures, only SACM applies. At intermediate temperatures SACM and CT approach each other; however;. Landau-Zener-type multiple crossings of adiabatic channel potentials introduce local nonadiabaticity which has to be accounted for. The high-temperature transition from globally adiabatic to nonadiabatic (sudden) dynamics is studied by CT. Thermal rigidity factors, accounting for the influence of the anisotropy of the potential on the-capture rate constant, are expressed in simple analytical form which facilitates practical applications. The present work complements similar studies on the addition of atoms to linear molecules in standardized valence potentials (part IV of this series). (C) 1998 American Institute of Physics.