THE REACTION OF NH2 WITH O

The reaction between atomic oxygen and the amidogen radical, NH2, has been studied at 295 K by infrared kinetic spectroscopy. The NH2 radica l was produced by excimer laser photolysis of NH3 at 193 nm and-reacte d with O atoms produced by a microwave discharge of dilute O-2/He mixt ures. IR transient absorptions of NH2, and of NH and OH radicals forme d as reaction intermediates, were monitored using a tunable infrared c olor-center laser. The room-temperature rate constant for the overall reaction was measured as (6.5 +/- 1.3) x 10(-11) cm(3) molecule(-1) s( -1). The minor channel leading to NH + OH was observed but accounted f or at most about 8% of the NH2 reacting. The rate constant for the rea ction NH + O was determined from fitting the NH time profile to be (6. 6 +/- 1.5) X 10(-11) cm(3) molecule(-1) s(-1).