Elastic resonant and nonresonant differential scattering of quasifree electrons fromB4+(1s)and

Abstract

High-resolution doubly differential cross-section measurements and calculations for quasifree electrons elastically scattered through 180°from ground-state He-and H-like boron ions are presented. The measurements, covering the entire (for B 3+ ) and (for B 4+ ) Rydberg series populated by resonant excitation, were performed by zero-degree Auger projectile electron spectroscopy of 3.91 MeV B 4+ and 3.08-7.48 MeV B 3+ ions in collisions with H 2 targets. The projectile energy dependence study is used to further investigate other background contributions such as direct electron capture, direct excitation, and nonresonant transfer excitation. R-matrix calculations, particularly sensitive at this large scattering angle to electron correlation, exchange, and interference effects, are found to be in excellent overall agreement within the electron scattering model.

Role of cascade and Auger effects in the enhanced population of theC3+(1s2s2pRohrbein1, Kirchner2, Fritzsche3 2010Phys. Rev. A2211531View full textAdd to dashboardCite

“…Recently, this enhancement of the 1s2s2p 4 P states was determined more quantitatively for 1.1 MeV/amu F 7+ (1s2s 3 S) impact on He and Ne [3]. For the case of He it was found that the measured ratio R = 4 P /( 2 P − + 2 P + ) was 2.9, 1 which has to be compared to the value of 2 expected from spin statistics [4][5][6].…”

Radiative Cascade Repopulation of 1s2s2p 4P States Formed by Single Electron Capture in 2–18 MeV Collisions of C4+ (1s2s 3S) with He

“…In our recent publication [30], the long-standing problem of how multi-unpaired-electron ion cores behave, while undergoing electron processes during fast atomic collisions, was treated both experimentally and theoretically. A viable way to explore this is to consider the 2p SEC channel in MeV collisions (Equation (36)). There, the ratio R of the similarly configured 1s2s2p 4 P to 2 P ± SEC cross sections, defined by Equation (37), should bear the corresponding population spin statistics signature.…”

“…In the case of 2p single electron capture (SEC) in collisions of 1s2s 3 S ions with He and H 2 , R has been considered to be an indicator of spin statistics [31][32][33][34][35]. Indeed, this ratio results in R = 1, when considering only spin multiplicity, while R = 2 in the frozen core approximation, where only the 4 P and a single 2 P state can be produced from the 1s2s 3 S initial state [34,36,37]. Such statistical arguments and approximations are often used to simplify difficult problems of computing relative populations in high energy plasmas [4] and can therefore be of important practical use.…”

K-shell photoionization of Be-like boron (B+) ions: experiment and theory

“…Previously, identification of K-Auger transitions from singly and multiply charged ionic states of boron has been performed experimentally by using electron spectroscopy in ion-atom collisions [40][41][42][43], photon absorption and emission by laser-produced plasmas [44,45], EII [46], beam-foil spectroscopy [47], high-resolution spark spectroscopy [48] and high-resolution PI spectroscopy employing synchrotron radiation [22]. Theoretically, resonance energies and linewidths for Auger transitions in the Be-like boron ion have been calculated using a variety of methods, such as 1/Z perturbation theory [49][50][51], unrestricted Hartree-Fock [52], configuration interaction for initial and final states [53], single or multi-configuration Dirac-Fock [45], the saddle-point-method (SPM) with Rmatrix or complex coordinate rotation methods [54][55][56][57][58], complex scaling, multi-reference configuration interaction (MR-CI) [59] the spin-dependent localized Hartree-Fock density-functional approach [60] and R-matrix theory [61].…”