ANOMALOUS DEPENDENCE OF RESISTANCE ON LENGTH IN ATOMIC WIRES

The resistance of an atomic Na wire between two macroscopic metallic e lectrodes is found to decrease by a factor of 2 going from the 1- to t he 2-atom wire, and then to stay roughly the same for the 2-, 3-, and 4-atom wires. The initial decrease in resistance is related to the phe nomenon of incomplete valence resonances for an atom interacting with a continuum of states. Such resonances lead to what might be called in complete conduction channels.