Relative rate constants for removal of vibrationally excited OH(X2πi)v=9 by some small molecules at room temperature

✍ Scribed by B. J. Finlayson-pitts; D. W. Toohey; M. J. Ezell

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 820 KB
• Volume: 15
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550150206

✦ Synopsis

Vibrationally excited OH in u = 9 [designated OHf(9)] was generated by the reaction of hydrogen atoms with ozone in a fast-flow discharge system at 300 f 3 K and a total pressure of 1.1 f 0.1 torr, with argon as the carrier gas. The addition of a species X, which can deactivate the OHt(9) or react with it, led to a decrease in the Meinel band chemiluminescent emission intensities at both 626 nm (9 -3 band) and 519 nm (9 -2 band), which were monitored as a function of the concentration of X. Application of the kinetic scheme developed previously for this chemical system gave the relative rate constant for the removal of OHt(9) by X. The relative rate constants determined in this study, taking 0 2 as the reference deactivator (k02 = l.O), are as follows: He _< 0.02; H2 5 0.05; SFs 0.09 f 0.01; CFd 0.19 fO.Ol;N203.5f0.4;N017.7f 1.5;H2074.3+2.9;DzO57.6f2.0;NH361.3f1.9;ND358.7 f 1.6; SO2 7.1 f 1.4; COS 8.4 f 1.7; H2S 33.7 f 8.4; CHa 1.56 f 0.03; CDI 1.06 f 0.06. Application of these relative rate constants to conditions in the upper atmosphere (60-100 km) suggests that OHt(9) is removed primarily by deactivation by 0 2 , and at altitudes 290 km, possibly by O(3P). However, since 0 2 is unusually efficient for a homonuclear diatomic in deactivating OH+(9), it may not be the primary deactivator for the lower ( u _< 8) vibrational levels. These results are compared to earlier studies of OHt( 9), and possible mechanisms of interaction of OHt(9) with these molecules are discussed.