Vibrational deactivation of CO (ν = 1) by inelastic collisions with 3He and 4He at low impact energies

Vibrational relaxation cross sections are calculated within the coupled-states approximation for COHe systems. Resonant structure in the cross sections is observed close to the vibrational threshold, and attributed to the formation of quasi-bound states due to the attractive part of the interaction potential. The contribution of these resonances to low-temperature vibrational relaxation rate constants is considered.