The Electron Affinity of Iodine from Space-Charge Effects

The electron affinity of iodine atoms has been determined by a direct method in which only iodine atoms and electrons were involved. The value so obtained is 74.6 k-calories, which is in good agreement with values obtained by other methods. The concentration of the several ions of different masses (I— and E—) have been calculated from their effect on space charge. It has been established that iodine has no effect on the thermionic emission of tungsten.