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

Vibrational relaxation of OH(X(2)Pi) in the nu = 9 state by O-3 and NH3 has been studied via flash-photolysis using high-resolution direct infrared ab sorption detection of OH in the nu = 11 <-- 9 band. OH(nu = 9) removal by O -3 occurs with a nearly gas-kinetic rate (k(O3) = 1.37(15) x 10(-10) cm(3)/ s). Collisional removal by NH3 (k(NH3) = 7.60(50) x 10(-10) cm(3)/s) is two to three times higher than the hard-sphere collision limit, suggesting a r esonant V-V energy transfer induced by long-range dipole-dipole interaction s. An upper limit of 5 x 10(-14) cm(3)/s is placed on OH(nu = 9) vibrationa l relaxation by argon. (C) 2001 Elsevier Science B.V. All rights reserved.