The Photolysis of Ammonia at 1849A in a Flow System

Abstract

An investigation has been made of the photolysis of ammonia at 1849A in a flow system at room temperature. The products of the reaction were found to be hydrazine, hydrogen, and nitrogen. The rate of decomposition of ammonia was independent of the linear flow rate but depended upon the ammonia pressure in the reaction zone. The fraction of ammonia decomposed which was recovered as hydrazine, while independent of ammonia pressure, increased markedly with increasing linear flow rate from zero in the static system to 0.84 at a linear flow rate of 1750 cm/sec. It was found that the quantum yield of ammonia consumption under flow conditions was consistently higher by a factor of approximately two than for the static conditions at the same pressures. A separate system was used to determine the extinction coefficient of ammonia at 1849A over the pressure range of the experiments. The value obtained was 1.21×103 liters-mole-1—cm—1. A mechanism has been proposed which is in qualitative agreement with the observed facts.