3.1.2.4 Work function data

This chapter discusses the theory and measurements of work function data for metals. The work function can be defined as the minimum energy required to extract one electron from the metal. The work function is certainly a basic property of any surface. Comparison of theoretical values of the work function with the results of experiments on polycrystalline samples is illustrated. Theoretical and experimental work functions of nine simple metals are tabulated. Experimental and theoretical work functions for three low index planes of aluminum are tabulated. Chemical potential is measured with respect to the crystal zero and a constant valence charge density is assumed in a muffin-tin region. The experimental methods used for calculation of work function are photoelectric method, angle-resolved photoelectron spectroscopy method, contact-potential difference method, thermionic method, field emission method and diode (retarding field) method.