Charge-transfer processes in atom and multicharged ion collisions have attracted extensive theoretical and experimental interest, due to their diverse applications in laboratory and astrophysical plasmas stemming from their large cross sections (proportional to the ionic charge) and pronounced final-state selectivity. However, for the Be3++ H collisions, the experimental charge transfer cross-section data are completely lacking because Be is toxic and it is also not easy to produce a properly calibrated hydrogen atomic target.
Researchers in Institute of Modern Physics, Chinese Academy of Sciences (IMP) studied the radiative and nonradiative charge transfer processes for the Be3+-H collision at energies below 10 keV/u.
The nonradiative charge transfer (NRCT) cross sections were calculated by using the quantum-mechanical molecular orbital close-coupling (MOCC) method. The molecular data were calculated by the ab initio method. The present NRCT results agreed well with the results calculated by atomic orbital close-coupling (AOCC) method. But the present results were several times larger than the results of semiclassical MOCC calculation of Shimakura. This might attribute to the variations of couplings obtained by the valence-bond method of Shimakura. The results showed that the capture to Be2+(3l) states was dominant in the whole energy range with the exception of about 3keV/u, where the 2l and 3l results are comparable. The rotational couplings play important roles.
In addition, the radiative charge transfer (RCT) process was investigated by the optical potential and semiclassical methods at 10-6-103 eV/u. It was found that, at energies below 40 eV/u, the NRCT cross sections decreased rapidly with energy and the RCT exceeds the NRCT process.
The results have been published in Phys. Rev. A87, 042709 (2013)
Fig.1 Total charge transfer cross sections for Be3+-H collision. (Image by IMP)
Introduction
