Thermionic Emission into Dielectric Liquids

The presence of thermionic emission at ordinary temperatures for cathodes in contact with dielectric liquids is demonstrated. The current voltage relation is shown to obey the law $I=I_0{e}^{\left(\frac{\epsilon {\left(\epsilon FD\right)}^{\frac{1}{2}}}{\mathrm{kT}}\right)}$, where $I$ is the current, $F$ the field, and $D$ the dielectric constant of the liquid. This is a modification of the Schottky law in vacuum. The effects of adsorbed hydrogen and oxygen, of surface irregularities, and of work function are discussed. The formation of a wax by electron bombardment of the liquid is also reported.