One and two electron processes in 0.9 keV/u to 60 keV/u Ar16++He collisions

Recoil-ion momentum spectroscopy

“…devices based on (pre-cooled) supersonic jet targets. Technical information on the various former concepts are found for warm static targets in Ullrich (1987), Ullrich et al (1987Ullrich et al ( , 1988b, for effusive targets in Levin et al (1987), Grandin et al (1988), for cooled static targets in Ullrich et al (1991), Ullrich (1994), Dörner et al (1991) and for effusive gas jet targets in Ali et al (1992), Frohne et al (1993Frohne et al ( , 1996, Wu et al (1994aWu et al ( , b, 1995 (see also the reviews by Cocke and Olson (1991) and Ullrich (1994)).…”

“…Pioneering experiments on the longitudinal momentum transfer to recoil ions after kinematic electron capture were performed for low-energy highly charged ion impact (Ali et al 1992, Wu et al 1993, Raphaelian et al 1995 as well as at larger projectile velocities (Frohne et al 1993, Wu et al 1994a. With a resolution of the pinholecollimated effusive jet of ±11 au in the directions transverse to the atomic beam propagation Frohne and co-workers were able for the first time to observe the backward scattering of the recoil ion as a function of the number of captured electrons n C following from the electron translation factor 1 2 n C v P (equation ( 3)).…”

“…With a resolution of the pinholecollimated effusive jet of ±11 au in the directions transverse to the atomic beam propagation Frohne and co-workers were able for the first time to observe the backward scattering of the recoil ion as a function of the number of captured electrons n C following from the electron translation factor 1 2 n C v P (equation ( 3)). The Q-value of the reaction was not accessible in this experiment due to the uncontrolled momenta of the emitted electrons but has been investigated later for single capture and transfer ionization collisions with a helium target (Wu et al 1994a(Wu et al , 1995. Using an improved experimental arrangement with a resolution of about ±0.75 au, Wu and co-workers were able to separate capture into the projectile K from L and higher shells.…”

“…With these spectrometers for the first time the complete momentum vector of one reaction product, the target ion, emerging from an atomic collision was measurable with a resolution of a few per cent of an atomic unit and a solid angle of nearly 100% of 4π. Experiments became feasible where contributions to the projectile ionization due to the electron-nucleus or electron-electron interaction were kinematically separated (Dörner et al 1994, Wu et al 1994a. State-selective scattering-angle-dependent studies of singleand double-electron capture into different shells of the projectile at medium velocities were performed (Mergel 1994, b, Wu et al 1994a, b, 1995, Kambara et al 1995, Abdallah et al 1997.…”

Identification of distinct two-electron transfer processes in O 6+ + Na collisions

“…This process results in the creation of doubly excited nln l projectile states, which decay either by photon emission or by Auger electron emission. In most studies noble gasses, in particular He (see, e.g., [1][2][3][4][5][6][7]), or H 2 [8,9], have been used as electron donors. This implies that one deals with the capture of two equivalent electrons.…”