1. Proceedings of a conference on “Small particles and Inorganic Clusters”, Lausanne, Switz., 1980, Surf. Sci., 106(1931)
2. Photoemission study of matrix isolated Cu atoms and clusters
3. Adsorption of molecular nitrogen on copper clusters and nickel films at 7 K
4. Photoemission from matrix-isolated nickel atoms
5. There is a very extended literature on this topic, only selected illustrative quotations are listed below: