Field-evaporation of magic cluster ions, C-20(+), from carbon nanotubes

Carbon cluster ions generated by field-evaporation from multiwall nanotubes (MWNTs) and single-wall nanotubes (SWNTs) have been analyzed by mass spect rometry. The observed mass spectra showed that the three magic clusters; vi z., the singly charged C-20 and two clusters having mass number higher than that of C-20, were generated as magic clusters. The onset Field strength f or observing C-20(+) was estimated to be about 10 V/nm. The intensity of Ct :, peak was rapidly decreased with time. The specific number of atoms compr ising C-20(+) indicates a dodecahedral structure or a corannulene instead o f a linear chain or a ring. (C) 2001 Acta Materialia Inc. Published by Else vier Science Ltd. All rights reserved.