Ionization on Platinum and Tungsten Surfaces. I. The Alkali Metals

The ionization of all of the alkali metals on tungsten and on tungsten oxide surfaces follows the Saha-Langmuir equation with no reflection. On platinum, however, a departure from this equation indicates partial reflection of the atoms. The reflection of Na is probably 0%, since the ionization efficiency is given closely by the Saha-Langmuir equation with a value of 5.50 ev for the work function of Pt at 2000°K. The same value of the work function then indicates reflections of 18% for Li, 48% for K, 22% for Rb, and 8% for Cs, at 2000°K.