The Normal Energy Distribution of Photoelectrons from Sodium

The theory of the normal energy distribution of photoelectrons has been reformulated by including the effect of contact potential; if photoelectric currents are plotted against applied retarding potentials, the apparent stopping potential at 0°K is shown to be independent of the cathode work function. Apparatus has been constructed for the precise determination of the normal energy distributions of photoelectrons from sodium. Photoelectric currents emitted by monochromatic light were measured after passage through a retarding field. The results of such measurements were found to vary with changes of the anode potential barrier. Energy distribution curves taken at different frequencies exhibit satisfactory mutual consistency; when plotted logarithmically they are of identical shape. This shape does not agree with the theoretically predicted normal energy distribution. An explanation for this discrepancy is given in terms of the structure of the anode potential barrier. A method for the determination of $\frac{h}{e}$ is suggested, which is based on the consistency in shape of the empirically determined curves.