Quenching of rotationally excited CO in cold and ultracold collisions with H, He and H₂

The study of molecular inelastic collision processes at cold and ultracold temperatures is of considerable interest as schemes are currently being developed to efficiently cool and trap neutral polar molecules. In this work, quantum-mechanical scattering calculations are presented for the quenching of rotationally excited CO due to collisions with H, He and H₂ for collision energies between 10^-5 and 10 cm^-1. The calculations were performed using the close-coupling approach and the coupled-states approximation. Cross sections for the quenching of the j ≤ 1-10, 20, 30 and 40 levels of CO are presented and mechanism and trends of energy transfer in these systems are discussed.