Computational investigation of internal excitation in nonreactive molecular collisions: Resonances in rotational excitation

Resonances in subexcitation molecular collisions are demonstrated by exact numerical solution of the close-coupled integral equations for rotational excitation including closed channels in the total-angularmomentum representation. These results serve as a reference for comparing various approximate theoretical predictions. In particular, the limitations of the adiabatic approximation are exhibited. The resonance energies can be essentially predicted by a "best local" potential approximation. The resonance line shapes are fitted by a simple Breit-Wigner form.