Fast vibrational relaxation of OH(v=9) by ammonia and ozone

Vibrational relaxation of OH(X2Π) in the v=9 state by O3 and NH3 has been studied via flash-photolysis using high-resolution direct infrared absorption detection of OH in the v=11←9 band. OH(v=9) removal by O3 occurs with a nearly gas-kinetic rate (kO3=1.37(15)×10−10 cm3/s). Collisional removal by NH3 (kNH3=7.60(50)×10−10 cm3/s) is two to three times higher than the hard-sphere collision limit, suggesting a resonant V–V energy transfer induced by long-range dipole–dipole interactions. An upper limit of 5×10−14 cm3/s is placed on OH(v=9) vibrational relaxation by argon.