Vibrational relaxation and quenching of CO(A1Π, ν = 0–8) in collisions with rare gas atoms

Steady state fluorescence experiments yielded effective cross sections for the vibrational relaxation and quenching in collisions of electronically excited CO molecules, in single vibrational levels ν = 0 to 8 of the A¹Π state, with rare gas atoms. Vibrational relaxation was found to proceed not only by Δν = 1 but also by Δν = 2 and Δν = 3 processes. The relaxation cross sections for the Δν = 1 processes decrease with increasing vibrational quantum number ν. The quenching data give strong evidence for collision induced intersystem crossing to nearby triplet states.