First state selective electron capture measurements with trapped highly charged ions

The first state selective electron capture cross section measurements at eV energies are reported for collisions between C4+ ions and H-2 molecules. The cross sections are measured in a crossed beam experiment by means of Photon Emission Spectroscopy. The ion beams are decelerated in an octopole ion trap where the trap is used to guide the ion beam through the collision region. The experimental results are in excellent agreement with previous measurements at higher energies. The 3-state atomic orbital calculations of Gargaud and McCarroll generally agree with our measurements although there are some discrepancies at lower energies. However, the results for C4+ are still on a relative scale. To put our measurements on an absolute scale the N4+ + H system is investigated at keV energies. These results are in good agreement with the data of previous experiments.</p

State-selective Electron-capture Measurements for N4+^{4+}-H and N4+^{4+}-H2 collisions

State-selective electron-capture cross-section measurements in the energy range between 1 and 4 keV/amu are reported for collisions between N4+ ions and atomic and molecular hydrogen. The cross sections are measured in a crossed-beam experiment by means of photon emission spectroscopy. The singlet and triplet states are resolved. It is found that the capture probabilities are not statistically distributed over both spin states and depend strongly on the primary energy. For collisions with atomic hydrogen the agreement with fully quantum-mechanical calculations is in general good. The sums of the experimental results for capture into all the singlet and triplet states are in excellent agreement with previous total one-electron capture measurements. Additionally for molecular hydrogen we performed multichannel Landau-Zener calculations that are found to be in fair agreement with the experimental data except for the highest angular momenta states. [S1050-2947(98)00701-X]

First state selective electron capture measurements with trapped highly charged ions

The first state selective electron capture cross section measurements at eV energies are reported for collisions between C4+ ions and H-2 molecules. The cross sections are measured in a crossed beam experiment by means of Photon Emission Spectroscopy. The ion beams are decelerated in an octopole ion trap where the trap is used to guide the ion beam through the collision region. The experimental results are in excellent agreement with previous measurements at higher energies. The 3-state atomic orbital calculations of Gargaud and McCarroll generally agree with our measurements although there are some discrepancies at lower energies. However, the results for C4+ are still on a relative scale. To put our measurements on an absolute scale the N4+ + H system is investigated at keV energies. These results are in good agreement with the data of previous experiments