Compound-State Resonances in Atom—Diatomic-Molecule Collisions

The theory of atom—diatomic-molecule collisions has been extended to include the coupling between open-and closed-channel states by means of the effective-Hamiltonian method as developed by Feshbach. The results have been used to discuss in detail compound-state resonances at energies below the first excitation threshold. Calculations are presented for the Xe+${\mathrm{H}}_2$ and Xe+${\mathrm{D}}_2$ systems. They suggest that compound-state resonances may be observable in molecular-beam experiments. These resonances are found to depend primarily upon the short-range anisotropic part of the interaction potential.