On the mechanism for collisional deactivation of vibrationally excited singlet molecular oxygen

In order to study in more detail the mechanism involved in the collisional deactivation of singlet molecular oxygen excited to the first vibrational level by means of laser irradiation, measurements of both amplitude and phase of the resultant acoustic pressure signal were measured as a function of frequency for 35 atm pure oxygen and a mixture containing 1 atm He and 34 atm O2. All significant features of the experimental data may be explained theoretically by assuming that the only significant deactivation paths are (a) a vibrational deactivation O2(1Δg) (ν′ = 1→0) followed by an electronic deactivation O2(1Δg) (ν′=0) → O2(3Σg−) (ν=0); and (b) an electronic deactivation O2(1Δg) (ν′=1) → O2(3Σg−) (ν=1) followed by the vibrational step O2(3Σg−) (ν=1→ 0).