Two types of mass abundance distributions for anionic carbon clusters investigated by laser vaporization and pulsed molecular beam techniques

Two types of mass spectra, for anionic carbon clusters C-n(-) have been rev ealed using laser vaporization and pulsed molecular beam techniques. The le ss structured mass spectrum characteristic of the magic-numbers at n = 5, 8 , 11, 15, and 17 is established at the early stage of the cluster formation process, namely in the laser vaporization process. The more structured one is featured for a regular odd-even alternation and the magic numbers at n = 10, 12, 16, 18, 22, and 28, and has been developed only after extensive c lustering and qnenching processes, where low-energy electron attachment pla ys a vital role. Transition between these two types of mass spectra can be realized by controlling either the strength of the pulsed gas flow or the s ynchronism between the gas flow and the laser vaporization.