Using the crossed-beams technique, we have measured absolute cross sections for the total production of in collisions between and ions by means of a beam-pulsing method for the detection for centre-of-mass energies between 1.4 and 39.8 keV. From the measured data cross sections for the electron detachment process were calculated using the total cross sections for mutual neutralization measured previously. The electron detachment results are in very good agreement with recent theoretical calculations.

By means of a crossed-beams technique we have measured absolute cross sections for the charge-transfer reaction by coincident detection of the product ions and for CM energies between 4 and 200 keV. Estimates of angular differential cross sections are made from measured scattering distributions of reaction products at CM energies of 5.15 and 15.86 keV. The total cross sections for charge transfer are calculated by close coupling of a two-centre atomic basis.

By means of a crossed-beams technique we have measured absolute cross sections for the charge-transfer reaction C3+ + He2+ --> C4+ + He+ by coincident detection of the product ions C4+ and He+ for CM energies between 4 and 200 keV. Estimates of angular differential cross sections are made from measured scattering distributions of He+ reaction products at CM energies of 5.15 and 15.86 keV. The total cross sections for charge transfer are calculated by close coupling of a two-centre atomic basis.

We report the first observation of interference in charge exchange collisions between two ions. Employing the crossed-beams technique in conjunction with signal recovery methods, angular differential cross sections have been measured for charge transfer in He2+ + He+ collisions at barycentric energies between 0.5 and 10.2 keV. The oscillatory structure observed is in agreement with quantum calculations and can be interpreted in terms of interference between scattering into gerade and ungerade molecular states, which arise due to the identity of the nuclear charges.

A crossed-beams experiment designed to study charge-changing collisions between singly charged ions has been modified to extend its applicability to collisions between multiply charged ions in a broader range of collision energies. Computer simulations of the beam transport system and the new electrostatic analyzing units are presented. The ion-optical predictions are tested experimentally. A data acquisition system that allows measurements of angular differential cross sections in ion–ion collisions is described.

Employing the crossed-beams technique in connection with signal recovery by coincident detection of the reaction products, we have measured total cross sections for the quasi-resonant charge exchange reaction C2+ + B+ → C+ + B2+ − 0.77 eV. The experimental data taken in the center-of-mass energy range between 1.26 and 158 keV are compared with previous and recent theoretical results.

Scattering distributions for charge exchange both in H++He+ collisions, the simplest ion-ion collision system, and He+ + He+ collisions have been measured at cm-energies between 5 and 16.5 keV. For the measurements, we have employed a crossed-beams technique and position sensitive detection of the neutral reaction products. In contrast to heavy collision systems, the observed cm-scattering angles are small (θcm ⪡ 1°), so the primary ion beam profile as well as the transformation between lab- and cm-system has to be taken into account when extracting angular differential cross sections from the scattering distributions.

Quasi-resonant charge-exchange reaction C2++B+ to C++B2+ by coincident detection of the product ions C+ and B2+ for CM-energies between 1.3 and 160 keV. The reverse reaction was also investigated in the energy range between 2.5 and 80 keV: B2++C+ to B++C2+. The theoretical treatment is based on the correlation diagrams for the system (CB)3+ and shows that distinct channels are responsible for the direct and inverse reactions. The results of calculations are in good agreement with me experimental data.

By means of an ion‐ion crossed‐beams experiment angular, differential cross sections have been measured for charge transfer in He2+‐He+ collisions at barycentric energies between 0.5 and 16.3 keV. The measurements show an oscillatory structure as predicted by theory. These oscillations can be interpreted in terms of the interference between scattering into gerade and ungerade molecular states, which arise due to the identity of the nuclear charges.

Employing the crossed-beam technique, we have measured absolute cross sections for neutralization of ${\mathrm{H}}^{\ensuremath{-}}$ ions in collisions with multiply charged ions ${\mathrm{Ne}}^{q+}$ ($q\ensuremath{\le}4$) and ${\mathrm{Ar}}^{q+}$, ${\mathrm{Xe}}^{q+}$ ($q\ensuremath{\le}8$) at center-of-mass energies ranging from 20 to 200 keV. It is found that the cross sections are independent of the target ion species. The data are in excellent agreement with quantum calculations. A universal scaling law for the neutralization cross section is given.

Employing the crossed-beams technique in conjunction with a beam-pulsing method, we have measured absolute cross sections sigma tot for the process H-+H- to H0+... for CM energies between 2.5 and 100 keV. Combining the present results with our previously measured cross sections for double-electron detachment ( sigma 00) and triple-electron detachment ( sigma 0+). We obtain cross sections sigma 0- for the single-electron detachment process from the relation sigma 0-= sigma tot- sigma 00- sigma 0+ The experimental data of singleand double-electron detachment are well described by theoretical results based on the non-stationary tunnelling approach. Both cross sections are calculated for CM energies between 0.15 and 300 keV. A new two-electron simultaneous transition mechanism is introduced. The importance of this process for the theoretical assessment of the experimental results is discussed.

An intersecting beam technique has been used to measure total cross sections for resonant charge transfer in 3He2+-4He+ collisions at barycentric energies between 4 and 200 keV. Our measurements, obtained using coincident detection of the reaction products, are in good agreement with theoretical predictions. Furthermore, they confirm a scaling law by Reinhold and Falcon (1988) for symmetric resonant charge transfer in one-electron systems at intermediate energies.

Employing the crossed‐beams technique, we have investigated electron‐detachment processes from H− in collisions with multiply‐charged noble gas ions. Absolute cross sections for single‐ and double‐electron removal have been measured at center‐of‐mass energies from 50 keV to 200 keV and ion charge states up to 8. The data is discussed with respect to conversion efficiencies of H− to neutral H0 in plasma neutralizers proposed for efficient neutral beam heating of future fusion devices.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation R. Schulze, F. Melchert, S. Krüdener, S. Meuser, S. Petri, M. Benner, E. Salzborn; Mutual electron detachment in collisions between negative ions. AIP Conf. Proc. 5 October 1992; 287 (1): 177–183. https://doi.org/10.1063/1.44774 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search

Employing the cross-beams techique, we have measured absolute cross sections for charge transfer in collisions [sup 3][ital He2+]+[sup 4][ital He+][r arrow][sup 3][ital He+]+4[ital He][sup 2+] in the centre-of-mass energy range between 4 keV and 200 keV.

Employing the crossed‐beams technique, we have investigated electron‐detachment processes from H− in collisions with multiply‐charged noble gas ions Aq+. Absolute cross sections for single‐ and double‐electron removal have been measured at center‐of‐mass energies from 50 keV to 200 keV and charge states q up to 8.The single‐electron removal cross sections are nicely produced by calculations based on a generalization of the Keldysh theory for multi‐photon ionization.

Employing the Giessen ion-ion crossed-beams facility, absolute cross sections have been measured for single- and double-electron removal from H− in energetic collisions with Arq+ (q ≤8) ions. The data is compared to CTMC calculations and is discussed with respect to conversion efficencies of H− into H0 beams in plasma neutralizers proposed for efficient neutral beam heating of next generation fusion plasmas.

For the first time, charge-changing reactions in collisions of two negative ions were investigated. Absolute cross sections for mutual ionization were determined for H− colliding with H−, using crossed beams and coincident detection of the reaction products. The centre-of-mass energy range covered in the experiment extended from 1.5 keV to 90 keV for the reaction channel H− + H− to H0 + H0 + 2e− and from 4 keV to 40 keV for the channel H− + H− to H0 + H+ + 3e−. The measured cross sections are compared with results of CTMC calculations obtained with different model potentials for the interaction between the outer electron and the H0 core