WHEN ARE THIN-FILMS OF METALS METALLIC .3.

A large amount of experimental information has indicated that very thi n films of metallic elements can exhibit nonmetallic behavior. even on metal substrates. These films undergo a gradual nonmetal to metal tra nsition with increasing film density or thickness. The nonmetallic beh avior can be related to electron localization due to strong electron-e lectron correlation in low dimensional systems, as indicated by the st rong, enhancement of electron efficient mass. The evolution in the ele ctronic structure associated with the nonmetal to metal transition bea rs a striking resemblance to the behavior observed for free metal clus ters. Part I [1]. outlined the general concepts of a nonmetal to metal transition in a thin film, while part II [2] critically examined thre e examples of nonmetal to metal transitions for thin film overlayers. This paper will discuss some surprising correlations between the elect ronic structure of divalent thin films on metal substrates and divalen t metal clusters that have been reported in the literature.