Vibrational relaxation of O2(X 3 Σ−g, v = 9–13) by collisions with O2.

Vibrationally excited O2(X 3 Σ−g) was generated in the UV laser flash photolysis of O3 and single vibrational level was detected via laser-induced fluorescence (LIF) in the B 3 Σ−u−X 3 Σ−g system. The time-resolved LIF of adjacent vibrational levels has been analyzed by the integrated-profiles method and the rate coefficients for single-quantum relaxation, O2(X 3Σ−g, v = 9–13)+ O2(v = 0)→ O2(X 3Σ−g, v − 1)+ O2(v = 1), have been determined. To the best of our knowledge, the rate coefficients for v = 12 and 13 are measured for the first time in the present study. The efficiency of relaxation is higher at lower vibrational levels, indicating that a small energy mismatch is suitable for the energy transfer. The vibrational level dependence of all the rate coefficients for the relaxation measured in the present study and previously reported by several groups can be rationalized by the energy gap law. [ABSTRACT FROM AUTHOR]