Resonant Electron Capture and Stripping inNe+-Ne Collisions at Energies of Several keV

Abstract

Measurements have been made for collisions in which ${\mathrm{Ne}}^{+}$ ions are incident upon neutral Ne atoms. The incident ions ranged in energy from 0.80 to 15 keV and were scattered through angles of from 3\ifmmode^\circ\else\textdegree\fi{} to 13\ifmmode^\circ\else\textdegree\fi{} in the laboratory coordinates. The target atoms were present in the form of a gas at a pressure sufficiently low to insure that the bulk of the scattered particles reaching the detectors had experienced only a single encounter with a target atom. Analysis of the scattered incident particles shows that the relative probabilities for electron capture, scattering without change of charge, and single electron stripping all oscillate rapidly as a function of scattering angle. This behavior is evidently the result of resonance of the ${\mathrm{Ne}}^{+}$-Ne system between the attractive and repulsive states characteristic of the homonuclear, diatomic molecular ion. The data are discussed in terms of this interpretation, and experimental values are presented for the energy difference (${E}_{r}\ensuremath{-}{E}_{a}$) integrated over the collision path of relative motion, ${E}_{r}$ and ${E}_{a}$ being the energies of the repulsive and attractive states, respectively. For the range of collisions studied, this integrated energy difference ranged from about 15 eV-\AA{} to about 120 eV-\AA{}. An approximate functional dependence of (${E}_{r}\ensuremath{-}{E}_{a}$) upon internuclear separation is obtained from the data.