ENERGY-TRANSFER IN THE GROUND-STATE OF OH - MEASUREMENTS OF OH(UPSILON=8,10,11) REMOVAL

OH collisional removal rate constants for upsilon = 8, 10, and 11 with O-2, N-2, CO2, N2O, and He are measured. Vibrationally excited OH mol ecules in upsilon = 5, 7, and 8 are prepared from the reaction of atom ic hydrogen with ozone, and selectively excited to upsilon = 8, 10, an d 11, respectively, with a pulsed infrared laser via direct overtone e xcitation. Subsequent collisional deactivation of these laser-populate d levels is probed as a function of collider gas partial pressure usin g a time-delayed, pulsed ultraviolet laser resonant with OH(B (2) Sigm a(+) -X (2) Pi) transitions. Fluorescence from OH(B (2) Sigma(+) -A (2 ) Sigma(+)) is detected. These results complete a series of removal ra te constant measurements for OH(X (2) Pi) up to upsilon = 12. Resonanc e enhancement effects in vibration-to-vibration energy transfer for CO 2 and N2O factor significantly in the vibrational-level-dependent rate constants. (C) 1997 American Institute of Physics.