The Relative Intensities of Positive Rays from the Isotopes of Lithium

The relative intensities of positive rays from the isotopes of lithium were investigated for various lithium compounds at different temperatures, using Dempster's method of positive ray analysis. It was found that there is in general a change in the ratio ${\mathrm{Li}}_7$/${\mathrm{Li}}_6$ with temperature, the ratio decreasing at higher temperatures and increasing at lower. An application of Richardson's law shows that the two isotopes have different work functions, ${\mathrm{Li}}_6$ having a greater work function than ${\mathrm{Li}}_7$. The ratio $\frac{b_6}{b_7}$ is constant over wide ranges of temperature for a given lithium compound, but is different for different compounds.