Production and decay of highly-charged fullerene ions

Highly-charged fullerene ions C ₆₀ ^z+ and C ₇₀ ^z+ with charge states up to z=7 have been produced in an electron impact ion source of a two sector field mass spectrometer by using ion source operating conditions similar to those used in EBIT sources. The stability of these ions was investigated quantitatively in the two field free regions of the mass spectrometer. It was found that besides C₂ evaporation the dominant fission process for ions with charges larger than +2 is the loss of a charged C ₂ ⁺ unit via a super-asymmetric charge separation reaction C ₆₀ ^z+ C ₅₈ ^(z–1)+ +C ₂ ⁺ and C ₇₀ ^z+ C ₆₈ ^(z–1)+ +C ₂ ⁺ , respectively. The most important finding from these studies is that this super-asymmetric dissociation reaction proceeds via a three stage reaction sequence involving an electron transfer reaction at the second stage between a receding C₂ unit and the remaining highly-charged fullerene cage.Based on a lecture given by S. Matt at the 1st Euroconference on Atomic Physics with Stored Highly Charged Ions, Heidelberg, 1995.