THE OZONIZER AND THE "LIGHT EFFECT"

The paper first reviews the present state of our knowledge of the so-called "Light Effect" consisting of a sharp decrease of the discharge current in an ozonizer tube on exposure to light. Results of studies made by different workers on the different aspects of the effect, e.g. its dependance on the nature of the gas used, on the intensity and frequency of incident radiation, on the variation of the applied voltage on temperature, on the manner of illumination and on the surface condition of the walls of the discharge space, are collected and systematised. It is shown that for a proper understanding of the effect it is essential that the mechanism of the discharge in the ozonizer be first understood. For this purpose oscillographic records of the discharge current have been made under different conditions ; these are reproduced in the paper. The theory of the effect as originally suggested by Mitra and later developed by the authors is discussed in detail. According to this theory the origin of the effect is to be traced to the action of light on the surface charges (produced under discharge) on the walls of the annular discharge space of the ozonizer tube. Mechanism of the discharge as also that of the formation of surface charge are explained.

The theories proposed by other workers are also reviewed.