Thermal work function shifts for polycrystalline metal surfaces

A new approach is presented fnr the calculation of the thermal shifts of th e work functions of polycrystalline metal surfaces by including the thermal expansion of the metal into the election density parameter as il ell as Fe rmi energy. Calculations of d phi /dT as a function of temperature are perf ormed for 74 elements, encompassing a total of 103 cases of various tempera ture ranges, phases and (in a few cases) orientations. II is shown that for a majority of metals d phi /dT is not a constant over a broad temperature range. Comparison of theoretical and experimental values indicates that the thermal lattice vibrations do not influence d phi :dT significantly. Our r esults would suggest that the use of a Kelvin probe to measure the thermal variation of phi may be problematic. (C) 2001 Elsevier Science B.V. All rig hts reserved.