The formation of NH(X3Σ‐) from the pulsed vacuum uv photolysis (λ > 105 nm) of NH3 was investigated. Using resonance fluorescence detection the kinetics of NH was studied at room temperature. NH could be observed for up to 2 s; the efficiency of removal of NH by collisions with the walls of the reactor is estimated to be of the order of 10−4. A reaction of NH with its parent molecule NH3 or with N2 was not detected. Upper limits for the rate constants of the reactions
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