Change of Work Function with Particle Size

2 Change of Work Function with Particle Size 

The work function of a solid is equivalent to its ionization potential. It is always lower than the ionization potential of the single atoms that make up the solid. These 

TABLE 5.2. Work Functions and Ionization Potentials of Alkali Metals  

4 ADSORPTION-INDUCED CHARGE TRANSFER AT SURFACES METALS AND INSULATORS 

The opposite situation from weak interaction of inert gases with the surface space charge is surface ionization, when the adsorbate is ionized by the substrate. This typically occurs in alkali-metal adsorption on transition-metal surfaces. In the more usual situation with chemisorbed molecules, only partial charge transfer occurs to or from the substrate to the molecule. If the negative pole of the molecule points toward the vacuum, the induced electric fields cause an increase in the work function. Table 5.4 lists the work-function changes obtained by the chemisorption of several molecules on rhodium. 

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