Journal of Chemical Physics, Vol.107, No.19, 7809-7815, 1997
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 molecules in upsilon = 5, 7, and 8 are prepared from the reaction of atomic hydrogen with ozone, and selectively excited to upsilon = 8, 10, and 11, respectively, with a pulsed infrared laser via direct overtone excitation. Subsequent collisional deactivation of these laser-populated levels is probed as a function of collider gas partial pressure using a time-delayed, pulsed ultraviolet laser resonant with OH(B (2) Sigma(+) -X (2) Pi) transitions. Fluorescence from OH(B (2) Sigma(+) -A (2) Sigma(+)) is detected. These results complete a series of removal rate constant measurements for OH(X (2) Pi) up to upsilon = 12. Resonance enhancement effects in vibration-to-vibration energy transfer for CO2 and N2O factor significantly in the vibrational-level-dependent rate constants. (C) 1997 American Institute of Physics.