Radiative electron capture by high-energy oxygen ions in hydrogen and helium

K-shell vacancy production in low-atomic-number (Zt = 17–29) solid targets has been measured in collisions of highly charged carbon ions with energies of 1.5–6 MeV u−1. The K-shell ionization cross sections of Cl, K, Ti, Fe and Cu are derived from the measured K x-ray cross sections. The present data-set has been used to test the predictions of a theoretical model based on the local plasma approximation (LPA). This theory takes into account the response of solid core electrons working within the dielectric formalism. We find that this ab initio ion–solid model gives very good agreement with the measured data for Fe and Cu targets, while it tends to under-estimate the data for the most symmetric collision systems studied here. We discuss the range of validity of the LPA in terms of the symmetry parameter and the impact velocity. On the other hand, a model based on the perturbed stationary state approximation, designed for ion–atom collisions (ECPSSR) is found to give excellent agreement with the measured data for all target elements over the whole energy range. All the measured cross sections for different targets are found to follow a universal scaling rule predicted by the ECPSSR.

Section: 31supporting

confidence: 91%

Experimental study of K-shell ionization of low-Zsolids in collisions with intermediate-velocity carbon ions and the local plasma approximation

Kadhane

Montanari

Tribedi

2003

“…[20]). Therefore we will again approximate the sum over the atomic states in (11) by neglecting ε n − ε 0 . For the bound and not very high-lying continuum states this can be done because for these states ω k ε n − ε 0 .…”

Section: General Approachmentioning

confidence: 99%

“…For the bound and not very high-lying continuum states this can be done because for these states ω k ε n − ε 0 . The high-lying continuum states in (11) do not contribute considerably to the dressing of the ground state ψ 0 and therefore the neglect of ε n − ε 0 in the corresponding terms in (11) is not expected to noticeably influence the result. Neglecting in (11) ε n − ε 0 and performing the summation over atomic states using the closure relation, we obtain for the outgoing state vector…”

Section: General Approachmentioning

confidence: 99%

“…The process of REC has been intensively studied, experimentally and theoretically, for almost three decades for both nonrelativistic and relativistic collisions (see e.g. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] and references therein, and also [16] for a review). Usually this process is considered in the rest frame of the projectile and regarded as a capture of a quasi-free electron.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Radiative electron capture as a collision-stimulated transition between electron states dressed by the radiation field

Voitkiv

Grün

2001

We consider radiative electron capture (REC) in fast nonrelativistic collisions of light atomic particles. In order to treat the process we adapted a formalism in which the REC is viewed as collision-stimulated transitions between electron states of different particles dressed by the radiation field. The formalism leads to frame-independent cross sections. Within the formalism the problem of defining the charge current operator does not arise. The results obtained for REC are close to those of Briggs and Dettmann (Briggs J S and Dettmann K 1974 Phys. Rev. Lett. 33 1123).

“…In the 'ordinary' radiative capture process only one electron is transferred to the ion and one photon is emitted. This process has been studied extensively for many years and a large amount of both experimental and theoretical results for this process covering collision energies from several MeV/u up to 160 GeV/u is available in the literature (see, for instance, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and references therein).…”

Section: Introductionmentioning

confidence: 99%

Two-electron capture with emission of one photon in fast collisions between a highly charged ion and a light atom

Voitkiv

Najjari

Toshima

et al. 2006

We consider the electron capture process in fast non-relativistic ion-atom collisions in which the transfer of two electrons from the atom to the ion is accompanied by emission of one photon with the mean energy ω (2) k about two times larger than that ω(1) k characteristic for the radiative capture of one electron. Such a photon can appear both due to the uncorrelated capture process, in which two electrons are transferred to the ion independently via the Coulomb and radiative capture channels, and due to the correlated two-electron capture, where the electron-electron interaction plays the crucial role. The uncorrelated capture produces the photon spectrum which has a maximum at ω (1) k and gives the main contribution to the two-electron capture. The correlated capture mechanism leads to very small capture cross sections but produces the photon spectrum having a maximum at ∼ ω (2) k which in principle enables to separate this process in experiment.