Heats of Condensation of Electrons and Positive Ions on Molybdenum in Gas Discharges

Abstract

New method for measuring the electronic work function.—A new calorimetric method for measuring the electronic work function of a metal in a gas discharge, has been developed. A small molybdenum sphere was supported in a region of intense gas ionization by three fine wires, two of which formed a thermocouple to measure its temperature, while the third carried the current of the incoming ions. Space potential and mean electronic energies $E_{-}$ were found by using the sphere as a Langmuir collector. Its rate of heating due to an increment $\Delta j$ in the electron current reaching it against a small retarding field was measured and equated (with small corrections) to $\Delta j(E_{-}+{\phi }_{-})$, whence the heat of electron condensation ${\phi }_{-}$ was found.