Eur. Phys. J. D 4, 1-6 (1998)
https://doi.org/10.1007/s100530050178

Electron multiplicity in slow collisions of Ar⁸⁺ ions with C₆₀

Laboratoire de Spectrométrie Ionique et Moléculaire (UMR-CNRS 5579) , Université Claude Bernard, Lyon I, Bâtiment 207, Campus de la Doua, 69622 Villeurbanne Cedex, France

Received: 25 March 1998
Accepted: 9 June 1998
Published online: 15 October 1998

Abstract

Electron capture by Ar⁸⁺ in collisions with C₆₀ fullerene has been investigated using coincident measurements of the number n of ejected electrons, the mass and charge of multicharged C recoil ions and their fragments C and the final charge state of outgoing projectiles Ar (). The number of captured electrons r is the sum of the numbers of stabilized and emitted electrons: r=n+s. The ratio n/s decreases by a factor three with s increasing from 1 to 7 showing that the multiply excited states populated by capture of a large number of electrons are rather stable against auto-ionisation. Each kinetic energy spectrum of Ar⁺ and Ar²⁺ projectiles is composed of two peaks which we attribute to collisions "inside" and "outside" the C₆₀ cage. The measured energy shift of the projectile keV is consistent with the corresponding energy loss keV in a carbon foil with an equivalent thickness. Inside collisions are characterized by a strong dissociation of recoil ions into light monocharged fragments and by a high multiplicity of ejected electrons.