Collision Dynamics of Three Interacting Atoms: The Faddeev Equations

An approach to atom‐diatom collisions is developed in terms of sums of spin‐dependent atomic pair interactions. Elastic, inelastic, atom‐exchange, and dissociative collisions are simultaneously considered within the Faddeev formalism, neglecting electronic excitation or ionization. These events may be described as successions of pair‐encounters where atomic spins are coupled in singlet or triplet states. At high energies a justification is given for the ``spectator stripping'' model for the reaction $\mathrm{A}+\mathrm{BC}\to \mathrm{AB}+\mathrm{C}$ and the corresponding probability amplitude is obtained. It is also found that the first correction to this model involves a ``displacement'' mechanism and an effective interaction between A and C.