ESR STUDY OF KINETICS OF REACTIONS OF D ATOMS AND O ATOMS WITH NH3

A wide temperature-range study using ESR atom detection has beem employed to measure the rates of the reactions of D atoms and O atoms with NH 3. In the case of the deuterium reaction, evidence is presented which shows that the interaction with NH3 proceeds via an exchange process of the type: D + NH3→NH3D+H. This reaction was studied over the temperature range of 423-741°K. The specific rate constant for this exchange reaction was found to be 1.9±0.2×1013 exp(-10 100±150/RT) in units of cubic centimeters mole -1-second-1. The reaction of O atoms with NH3 was studied over the temperature interval of 361-677°K. The specific rate constant obtained for the reaction O+NH3→OH+NH2 was found to be 4.0±0.9×1012 exp(-6600±130/RT) in units of cubic centimeters mole-1-second-1. This Arrhenius pre-exponential factor depends on a stoichiometric factor of 3.50 atoms per NH3 molecule assumed from other work.