Photoionization of Alkali Metal Vapors

Abstract

The vapors of potassium, rubidium, and cesium have been photoionized with light absorbed in the discrete region of the atomic spectrum. The energy threshold for the ionization process has been determined and the ions produced identified by mobility measurements. The data give lower limits for the dissociation + + + energies of K, Rb2 and Cs2. Each of these molecular ions has a bond energy approximately 50% greater than that of the corresponding neutral molecule. In addition, lower limits for the electron affinities of the alkali atoms and values for the mobilities of Rb+ , + Rb2 + + Cs and Cs2 in their present vapor are given.