Ionization cross sections of small cationic carbon clusters in high-energy collisions with helium atoms and stability of multiply charged species

This is the authors' abstract. We don't add key points for this paper.

Single, double, triple, and quadruple ionization cross sections of small cationic carbon clusters Cₙ⁺ colliding with helium atoms at a fixed velocity (2.6 atomic units) have been measured. The size ranges from $n=1$ to $n=10$ for single to triple ionization, from $n=5$ to $n=10$ for the quadruple ionization. The dependence of the cross sections with the cluster size is found to be well reproduced by predictions of the independent atom and electron (IAE) collision model. This extends the applicability of this simple model to higher n values and to a higher ionization degree than previously done [M. Chabot et al., Eur. Phys. J. D 14, 5 (2001)]. The branching ratios of multiply charged Cₙq+ clusters remaining intact over a 1000.3em0exns time window have been measured ($n=3--10$, $q=2--3$). Branching ratios of nonfragmented doubly charged clusters have been interpreted on the basis of calculated internal energies of Cₙ²⁺ due to single ionization of Cₙ⁺ clusters using the IAE model. This allowed estimates of the minimum energies required to fragment these Cₙ²⁺ species to be derived.