Kinetics of the reaction NH2((X)over-tilde2B1, ν2=0 and 1)+NO

The rate constants for reactions NH2((X) over tilde B-2(1), nu(2) = 0 and 1) + NO have been determined at 298 +/- 1 K using the pulsed UV photolysis/pulsed laser-induced fluorescence (LIF) technique. NH3 was photolyzed with an ArF excimer laser (193 nm), and NH2((X) over tilde B-2(1), nu(2) = 0 and 1) were detected by LIF in the (A) over tilde (2)A(1) - (X) over tilde B-2(1) system. It has been found that CF4 is efficient at vibrational relaxation of NH2, and the rate constant for deactivation of NH2((X) over tilde B-2(1), nu(2) = 1) by CF4 has been determined to be [3.2 +/- 0.5(2sigma)] x 10(-11)cm(3) molecule(-1) s(-1). Fast vibrational relaxation of NH2 by CF4 prior to the reaction with NO permits us to obtain an accurate rate constant for NH2((X) over tilde B-2(1), nu(2) = 0) + NO. The rate constant measured in N-2 buffer gas at I Torr is [2.05 +/- 0.1(2sigma)] x 10(-11) cm(3) molecule(-1) s(-1). The sources of discrepancy in previously reported room-temperature rate constants have been discussed on the basis of a survey of the experimental conditions and the methods of analysis. The overall rate constant for NH2((X) over tilde B-2(1), nu(2) = 1) + NO has been also obtained (without CF4) to be [2.6 +/- 0.4(2sigma)] x 10(-11) cm(3) molecule(-1) s(-1).