CARBON ANIONS AND DIANION CLUSTERS

The techniques and equipment developed for AMS studies are well suited for identifying exotic negative ions. On learning that double-negativ e ions consisting of clusters of seven or more carbon atoms were tenta tively identified using conventional mass spectrometry, we decided to use the AMS system at the University of Pennsylvania to incontrovertib ly confirm the existence of these molecular dianions. Also Coulomb exp losion studies have been made in the terminal of our tandem using carb on foils preceding Lexan track detectors to shed light on their struct ure, Similar, but preliminary searches for polyatomic dianions of Li, B, and Si were unsuccessful. We have also studied the polyatomic anion s of several light elements of general interest to the AMS community a nd, for example, were surprised to observe N-14(2)-, and N-14(3)- ions to be stable or to have lifetimes > 10 mu s.