Negative ions and their behavior in collisions

Abstract

We present a review of electron detachment cross sections of atomic, molecular, and cluster anionic projectiles colliding with atoms and molecules, the main focus being on reporting systematic experimental studies. These studies use an experimental method developed at our laboratory, which uses the gas cell of standard tandem accelerators as a collision target. The experimental data show that the velocity dependence of electron detachment cross sections can be described modeling negative ions as a quasi-free electron bound to a neutral core. Using this model, a velocityindependent contribution to cross sections is associated with the neutral projectile core, while a velocity-dependent curve is associated to the projectile quasi-free electron. This latter curve is the convolution of experimental free-electron cross sections, for the same target, with the momentum distribution of the quasi-free projectile electron. This model is useful to obtain cross section estimates, as exemplified by its application in several collision systems relevant for inertial fusion and plasma diagnostics. It is also a powerful tool for verifying the accuracy of anion structure calculations.

Quantifying absolute carbon isotope ratios by AMS

“…de Castro Faria et al give a recent review of their work [16], but particularly useful data are found in Luna et al [17] and Jalbert et al [18]. Lower energy cross-sections, especially the linear dependence of 2 and 3 electron loss from carbon anions, are found in Tsuji et al and Ishikawa [19,20].…”

Total detachment cross sections of C−, CH−, C2−, and CNascimento1, Mello2, Magnani3 et al. 2013Phys. Rev. ASelf Cite8010View full textAdd to dashboardCite

“…Details about the method and our experimental setup were given in previous publications [31][32][33][34][35][36][37], and only the main features are described here. The method is based on the use of the high-voltage terminal as the collision chamber, with the collision target being what is traditionally used only as a gas stripper to produce positive ions and neutral species at the second stage of the accelerator.…”