Quantum Size Effects in Small Metallic Particles

Abstract

Parallel to the development of surface science and catalysis research over the past 15 years has been the growth of a small but active inquiry, primarily by physicists, into the interesting physical properties expected of a collection of metallic particles or clusters of diameters less than 100 Å. Although the focus of interest, approaches, and aims of this inquiry have differed greatly in the past from those of catalysis research, the fact that both fields study basically the same physical object leads one to expect their eventual convergence, and at the recently held First International Conference on Small Particles [l] it was clear that this has now taken place. However, since many scientists engaged primarily in the study of surfaces and catalysis are not presently familiar with the physicists' work on small particles, it is the purpose of this paper to provide an introduction to the motivations for their research, to its current state, and to some of its probable future directions. This should be of interest to catalysis research because the physics studied is basic to that of real, practical catalysts in many cases, and because some of the experiments have been conducted on well-known catalytic materials [2], The field is still at a very early stage of growth, with much uncertainty and many unsolved problems, so that this article can at best raise interesting questions with the expectation that answers will become clear as the development of the field accelerates.