Coadsorption of Hydrogen and Potassium on Tungsten. Adsorption of Hydrogen on Potassium

Abstract

The adsorption of molecular and atomic hydrogen on multilayers of potassium, deposited on a tungsten field emitter, and the coadsorption of hydrogen and potassium on tungsten have been investigated by a field-emission technique. Molecular hydrogen does not appear to be chemisorbed on potassium at low temperatures. Atomic hydrogen seems to interact, most probably by the formation of a hydride structure with K atoms outermost from the surface. The coadsorption of H and K on tungsten leads to a decrease in work function over that caused by potassium alone, and to increases in the temperature required for potassium surface diffusion on tungsten. These facts are explained in terms of a surface complex WHK in which H is negatively charged relative to K.