STATE-SPECIFIC RATE CONSTANTS FOR THE RELAXATION OF O2(X(3)SIGMA(G)(-)) FROM VIBRATIONAL LEVELS NU=8 TO 11 BY COLLISIONS WITH NO2 AND O2

Rate constants are reported for the state-specific vibrational relaxation of O2(8 less-than-or-equal-to upsilon less-than-or-equal-to 11) by NO2 and 2 at 295 K. O2 is formed in vibrational levels up to v=11 by the reaction of O(3P) atoms with NO2. The oxygen atoms were created by partial photolysis of NO2 at 355 nm using a frequency-tripled Nd:YAG laser, and the kinetics of O2 in particular upsilon levels observed by laser-induced fluorescence in the (0, upsilon) bands of the B 3SIGMA(u)- -X3SIGMA(g)- system. The rate constants for relaxation of O2 by NO2, in units of 10(-13) cm3 molecule-1 s-1, are 5.5 +/- 1.2, 6.8 +/- 1.1, 9.3 +/- 1.2, 7.0 +/- 0.8 for v= 8, 9, 10, 11, respectively, and by O2, in units of 10-11 cm3 molecule-1 s-1, are 8.5 +/- 1.7, 10.8 +/- 1.7, 8.2 +/- 1.4, 7.5 +/- 0.3 for upsilon=8, 9, 10, 11, respectively. The results are compared with those obtained previously for higher vibrational levels of O2, and their implications for atmospheric chemistry are discussed briefly.