Electron capture and loss by kilo-electron-volt oxygen atoms in collisions with He,H2,N2, and

Abstract

Absolute differential cross sections are reported for electron capture and loss by ͑1-5͒-keV oxygen atoms incident on He, H 2 , N 2 , and O 2 for scattering angles between 0.02°and 1.73°in the laboratory frame. The form of the differential cross sections is seen to vary significantly with energy and between different targets. Differences between the present O-atom electron-loss cross sections and those for H atoms reported previously imply that the underlying physical mechanism may not be the same. The integral cross sections, also reported here, are consistent with most previous studies. The consensus of the available electron-loss data suggests that the cross sections of Fogel et al. [Soviet Phys. JETP 35, 601 (1959)] are in error.

Quantifying absolute carbon isotope ratios by AMS

“…8, flattened responses rising from low to middle energies are exhibited that are not parallel to that averaged trend. Lindsay et al [29] confirm this slope change for oxygen ionized in He, H 2 , N 2 , and O 2 , while finding Fogel's equivalent data 50-300% too low. Thus, we rejected the simple log-normal function from Fleischmann et al [28] for r 01 and simulated the ionization cross-section in our model with the sum of a log-normal for the high energy region and a low-kurtosis product of log-normal functions (exp À(ln(x/x0)/ r )^4 ) for the mid-energy data, as shown by the solid line of Fig.…”

“…Double electron capture on atomic carbon came from the helium target of Nakai and Sataka [38], scaled according to Sanders et al [27] for argon. All crosssection data are uncertain by at least 15% and some, such as the critical atom ionization of Fogel et al [24] and Ormrod and Michel [22] may be 200% or more in error [29]. Cross-sections to and from the 3+ reservoir had magnitudes equal to equivalent the 2+ state with the energy centroids of the log-normals at 2000 and 200 keV for ionization and EC.…”

MeV negative ion source from ultra-intense laser-matter interaction

“…For high energy neutral oxygen atom collision with another oxygen atom at rest, the electron loss cross section is: σ 01 ≈ 6 × 10 −16 cm 2 (O → O + ) and σ 0 − 1 ≈ 1 × 10 −16 cm 2 for the electron capture (O → O − ). [7][8][9] These cross-sections remain nearly constant for impacting particle energies in the range of a few hundred keV. In the electron capture and loss processes (1) one would expect that the largest contribution to the generation of O − comes from the ions, which have originally single positive charge, as these two species are close in the charge-exchange reactions chain.…”

Cross sections for electron capture and loss by keV oxygen atoms in collisions with CO and CO2

“…However, a review of the literature reveals that processes resulting in the reionization, and therefore loss, of oxygen ENAs have received little study [ Dehmel et al , 1973]. In fact, it is only because of recent advances in experimental technique that O atom electron capture and loss cross sections are available for any of the constituents of the Martian atmosphere at the relevant energies [ Lindsay et al , 2004]. For CO 2 , the electron capture and loss processes considered here may be represented, respectively, by the two equations, In this work, absolute angular differential cross sections (DCSs) for electron capture and loss by 2–5 keV O atoms incident on CO and CO 2 for scattering angles between 0.02° and 1.73° in the laboratory frame are presented together with 1–5 keV integral cross sections.…”