Some Photoelectric and Thermionic Properties of Rhodium

A thin ribbon of rhodium was subjected to rigorous heat treatment at 950°-1450°C for 1050 hours in a final vacuum of ${10}^{-8\mathrm{}}$ mm of Hg in order to put it in a stable condition for photoelectric and thermionic measurements. During this period the long wave limit shifted from about 2530A to 3150A and then shifted back to 2509A where it remained during the latter 375 hours of heat treatment.