Dissociative double capture in¹⁸O⁸⁺+ CO₂collisions¹

Abstract

The first results for electron emission associated with dissociative and non-dissociative capture processes in low velocity 18 O 8+ + CO 2 collisions are discussed. The electron spectrum is very similar to those obtained with heavy atomic targets; it is typical of multiple capture processes followed by autoionizing cascades, with strong lines superimposed on a weak continuum. No indication of a molecule target effect is found. It is shown that detailed information can be extracted from the dissociation patterns which concern the excitation of the target. As an example, the population of O 6+ (4l4l ) states is analysed thoroughly. It is shown to correspond mainly to a double capture process accompanied by a target excitation. When the autoionization has occurred, the target dissociates into various channels for which kinetic energy release distributions are obtained. The similarity between the present findings and photoionization data is emphasized.

Complete Coulomb fragmentation of CO2in collisions with 5.9 MeV u 1Xe18 and Xe43

“…More complex triatomic molecules like CO 2 , N 2 O, NO 2 or CS 2 have been investigated, mostly in photo-fragmentation experiments [7][8][9][10][11][12][13],and a few collisioninduced fragmentation studies have also been performed recently [14][15][16][17]. However, due to the complexity of the contributing molecular states most of the experiments so far concentrated on the determination of ionization or capture cross sections [18][19][20]; only a few experiments deal with a measurement of the kinetic energy released in the fragmentation process, mostly restricted by kinematically incomplete techniques [21][22][23]. In this paper we report on the kinematically complete study of CO 2 fragmentation in collisions with fast, highly charged ions; a special position-and time-sensitive multi-particle detector allows the determination of the released kinetic energy as well as the angular correlations between all fragments.…”

Variability of Cometary X-Ray Emission Induced by Solar Wind Ions

“…Highly charged ions moving at solar wind velocities capture electrons into a range of excited states with a distribution that depends on the charge and energy of the ion and on the identity of the target species that, for comets, is primarily the water molecule with lesser abundances of CO, CO 2 , OH, O, and H. Multielectron charge transfer can occur at low collision velocities (Posthumus & Morgenstern 1992;Kamber et al 1999;Beiersdorfer et al 2000;Greenwood et al 2000;Moretto-Capelle, Bordenave-Montesquieu, & Bordenave-Montesquieu 2000), but the resulting excited ions decay mostly by emission of energetic Auger electrons (Posthumus & Morgenstern 1992;Kamber et al 1999;Moretto-Capelle et al 2000) and rarely produce Xrays. X-ray emission arises from single-electron capture into specific excited states (Janev & Winter 1985;Suraud et al 1991;Janev 1995;Greenwood et al 2000;Beiersdorfer et al 2000).…”