UPS of 2–30-atom carbon clusters: Chains and rings

Abstract

Ultraviolet photoelectron spectra (UPS) of negative carbon clusters are reported in the size range from 2 through 29 atoms. The clusters were prepared in a supersonic beam by laser vaporization, and a F 2 excimer laser (7.9 eV) was used for photodetachment. The resultant UPS data indicate that carbon clusters in the 2–9-atom size range take the form of linear chains: the even-numbered chains having open shell electronic structures with high electron affinity, the odd chains having closed shell singlet ground states (for the neutral) and substantially lower electron affinity. Clusters in the 10–29-atom range give UPS patterns consistent with a monocyclic ring structure.