Absolute rate parameters for the reaction of atomic hydrogen with hydrazine

Absolute rate parameters for the reaction of atomic hydrogen with hydrazine H+N2H4→H2+N2H3 have been determined in a direct manner using flash photolysis of dilute mixtures of hydrazine in helium and time dependent observation of H via resonance fluorescence. By measuring the H-atom decay under pseudo-first-order conditions, the bimolecular rate constant k1 was obtained over the temperature range 228–400°K. The data were fitted with good linearity to the Arrhenius expression k1= (9.87±1.17) ×10−12 exp(−2380±100/RT) cm3 molecule−1⋅sec−1. The data were shown to be free of any contributions from secondary reactions involving H as a reactant or product. A comparison of the present results with those from previous studies employing discharge flow methods is presented.